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AEM spotlight:

AEM alumnus Jun Cui at GE Research

In his education, AEM alumnus Jun Cui sought balance. With a theoretical background in mathematics and mechanics, Cui says AEM was a natural fit due to the expertise of his adviser, AEM Professor Richard James. During his Ph.D. work, he developed a strong background in solid mechanics and learned proper methodology and rigor in experimentation from AEM Professor Tom Shield. Cui then accepted a postdoctoral position centered on new methods of the combinatorial synthesis of materials at the University of Maryland before taking a position as a materials scientist at GE Research.

For Cui, it all began with research into shape-memory materials at Minnesota. Shape-memory materials are materials that can undergo large changes of shape but return to their original shape when heated. They are now used in a variety of applications, from stents to hydraulic couplings, but in the early 1990s, beginning from theory, Professors James and Shield suggested there might be a related effect in ferromagnetic materials. In this case, instead of heating the material to cause it to return to its original shape, one simply brings a magnet close to the material.

“We realized that this would be a fascinating new material to understand from a scientific viewpoint, but also that it could do something that no other actuator could do,” James says. “That is, it could be made to undergo a big change of shape without actually touching the material, without any wires attached. For example, in biomedical applications, the piece of material could be inside the body, but the magnetic field could be applied from the outside.”

When Cui began his doctoral education in 1997, much of the subject was new, and James was at the forefront in theory, Cui says.

“I sought to understand his theory and try to validate that through experiments,” Cui recalls. “The challenge was to understand what material properties would enhance this ferromagnetic shape-memory effect. This research laid the foundation for where I am now.”

Cui’s experiments informed James’ research a great deal regarding ferromagnetic shape-memory, the professor says, adding, “The iron-palladium system that he discovered, and the basic principles that emerged from his thesis, are now at the heart of our understanding of this fascinating effect.”

After completing his doctorate, Cui desired more experience in experiments on shape-memory materials. Where James is a pioneer in theory, Cui says, his postdoctoral advisers, Manfred Wuttig and Ichiro Takeuchi from the University of Maryland, are arguably the top researchers on the experimentation and synthesis of shape-memory materials.

“I got the best of both worlds,” Cui recalls of his education. “It turned out to be a good choice.”

While at the University of Maryland, Cui’s broad background in shape-memory material theory paid off. Using large-scale combinatorial chemistry, Cui created and studied the composition and properties of hundreds or thousands of materials at a time. Cui also continued to work with James, Shield and Wuttig to parlay a new theory expounded by James into a proposal for a highly-competitive NIH grant that eventually led to head authorship in an article in the prestigious Nature Materials.

“Cui was able to bring Takeuchi’s powerful synthesis methods into the field of active materials, which previously had relied on painstaking synthesis of one sample at a time, often with great difficulty. Suddenly, thanks to Cui, we had hundreds of samples of different compositions, and we could test theory in a way that was not previously possible,” James says. “We learned something amazing about the origins of hysteresis, completely contrary to what is written in textbooks.”

After his time at Maryland, Cui felt it was time to move on from shape-memory materials alone and into industry, specifically to GE Research. At GE, Cui still uses methodology from his days at AEM and Maryland, as well as the massive combinatorial chemistry methods. Late last year, he wrapped up research into novel hydrogen storage materials, freeing up time to focus on his other research areas – mostly water-splitting research and research into low-cost materials for detection of NOx gases, which combine with water to form acid rain.

By 2010 or 2015, the EPA is going to roll out new regulations for how much NOx can be emitted, Cui says, which will make such a cheap material extremely important for keeping costs down for industry. Presently, a sensor at the level to be required by the EPA does exist, but is too costly to be practical. “The way it is done today relies on elegant electrochemical methods, but it is a $200 sensor,” Cui says. “Trucks need two of them and each lasts only three months right now, so we need to find something cheaper; we’re aiming for a $20 sensor that lasts for 3,000 hours.” Now that his everyday work does not deal with his research topic of choice while at AEM and Maryland - shape-memory materials - Cui says he utilizes his education mainly in the way he approaches a problem or an apparent dead-end. “I do research in different areas than I did as a Ph.D. student or a postdoc, but I constantly practice the method of thinking I learned,” he explains. “If I hit a dead end, I can figure out how I get around it - that’s what I use from my education – the method of thinking.”

In addition to his work at GE, Cui is presently an adjunct professor at the University of Maryland and is actively working with Shield and James on a variety of projects that come from their previous work on shape-memory materials.

Last Modified: Thursday, 29-Jun-2017 14:05:40 CDT -- this is in International Standard Date and Time Notation