August 2016: See Rosemary Barber to add or drop Physics classes

Do you need to add or drop a Physics class? Please see Rosemary Barber in Clark 121 from 7am – 12pm or 1pm – 3pm. You can get to her office by entering the doors in the Clark breezeway near the bicycle rack, from the corridor from Rockefeller Hall, or from the door at the top of the Clark patio that enters the back hall near Rockefeller. The Physics office at 117 Clark Hall is not a pass-thru to the back hall. Thank you.

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$23M NSF grant powers new science, technology center

A collaboration of scientists, led by Cornell University, has been awarded $23 million by the National Science Foundation to increase the intensity of beams of charged particles while lowering the cost of key accelerator technologies. This Science and Technology Center (STC) will contribute to scientific advances in disciplines including chemistry and biology by enhancing accelerator capabilities.

Particle accelerators generate powerful X-ray and electron beams that reveal the structure of biological molecules and materials, produce collisions that replicate conditions in the early universe or reveal the structure of the proton, and serve critical functions in manufacturing.

“Beam science enables these devices, but questions in beam science require a new approach,” said Ritchie Patterson, principal investigator for the Center for Bright Beams (CBB) at Cornell. “To realize the full potential of beams for science and industry, we need to combine the expertise of accelerator physicists with the knowledge and tools of scientists and mathematicians from a wide range of disciplines.”

To read the entire Cornell Chronicle article, click here.

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September 2016: Humanity helper: CHESS-made device rode into space

Better pharmaceuticals are out of this world: A new crystallization plate, developed and tested at the Cornell High Energy Synchrotron Source, or CHESS, hitched a ride to outer space and is helping a major drugmaker learn about protein structure.

On April 8, the In-Situ-1 crystallization plate – developed by Robert Thorne, professor of physics, and the company he founded, MiTeGen, LLC – was used in experiments for Eli Lilly onboard the history-making SpaceX CRS 8 mission.

To read the entire Cornell Chronicle article, click here. 

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Three A&S assistant professors win research grants

Twelve Cornell assistant professors, including three from the College of Arts & Sciences, have been awarded research grants by the Affinito-Stewart Grants Program.

The program, administered by the President’s Council of Cornell Women (PCCW), aims to increase the long-term retention of women on the Cornell faculty by supporting the completion of research important in the tenure process.

For the 2016 awards, 16 proposals were reviewed and rated by Cornell faculty members across the university and by the PCCW Grants Committee. Criteria for the review process were scholarly merit, research design, feasibility and likely relevance to promotion to tenure.

The council awarded a total of $101,615 in project funding to the 12 recipients. To honor the memory of former Cornell President Elizabeth Garrett, special mention was given this year to two grants that addressed cancer research, awarded to Pamela Chang and Gerlinde Van de Walle.

The 2016 A&S recipients are:

  • Athena Kirk, assistant professor in classics, $6,600 for “The Tally of Text: Catalogues and Inventories Across Greek Literature and Epigraphy.”
  • Julilly Kohler-Hausmann, assistant professor in history, $5,150 for “The Politics of Abstention and Demobilization in America’s ‘Right Turn.’”
  • Katja Nowack, assistant professor in physics, $8,445 for “Imaging Current in Quantum Materials with High Spatial Resolution.”

Other recipients are:

  • Ludmilla Aristilde, assistant professor in Biological and Environmental Engineering, $8,820 for “Annotation of Molecular Structures in Natural Organic Matter.”
  • Ilana Lauren Brito, assistant professor in Biomedical Engineering, $10,000 for “In Search of Probiotic Genes: Tracking Evolutionary Signatures of Co-evolution.”
  • Pamela Chang, assistant professor in Microbiology and Immunology, $10,000 for “Regulation of the Host Immune System by Gut Microbial Metabolites.”
  • Heather Huson, assistant professor in Animal Science, $10,000 for “Uncovering the Genes Regulating Athletic Performance in Alaskan Sled Dogs.”
  • Motoko Mukai, assistant professor in Food Science, $10,000 for “Reproductive Toxicity of Silver Nanoparticles.”
  • Jeongmin Song, assistant professor in Microbiology and Immunology, $3,600 for “In Vivo Study to Define the Cause of Typhoid Encephalopathy.”
  • Gerlinde Van de Walle, assistant professor in the Baker Institute for Animal Health, $10,000 for “Establishment of Xenograft Models of Mammary Cancer to Evaluate Potential of Epigenetic Drugs in Veterinary Oncology.”
  • Elia Tait Wojno, assistant professor in the Baker Institute for Animal Health, $9,000 for “Regulation of Immune Responses during Parasitic Worm Infection.”
  • Roseanna N. Zia, assistant professor and James C. and Rebecca Q. Morgan Sesquicentennial Faculty Fellow in Chemical and Biomolecular Engineering, $10,000 for “Computational Tools to Identify the Macroscopic and Microscopic Signatures of Gel Collapse: Interfaces and Pressure.”

Grants between $1,000 and $10,000 are given by the program each year. More than $1.1 million in research grants has been awarded to 237 women at Cornell since 1992.

This article first appeared in the Cornell Chronicle.

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June 2016: Graphene used as a frequency mixer in new research

A professor, a postdoctoral researcher and a graduate student hop onto a trampoline.

No, it’s not the opening line of a joke. It’s a setup for the explanation of new Cornell-led research involving the wonder material . A group led by Roberto De Alba, graduate student in physics, and Jeevak Parpia, professor and department chair of physics, has published a paper in Nature Nanotechnology regarding yet another application for the versatile, super-strong, super-light material.

Their paper, “Tunable phonon-cavity coupling in graphene membranes,” was published June 13 and describes the ability to use the graphene’s tension as a sort of mediator between vibrational modes, allowing for direct energy transfer from one frequency to another. De Alba was lead author.

Now, back to the trampoline. Let’s establish that the professor jumps at a slow rate, the postdoc at a medium rate and the grad student at a fast rate. They represent the natural modes of the trampoline, which represents the graphene.

If the professor initiates his slow jumping first, followed by the grad student at a much faster rate, the postdoc – by virtue of the jumping that is already going on – is forced into jumping, at his own rate. What’s more, the professor’s jumps become much higher than they were initially, as energy is transferred to him from the faster jumpers. This scenario won’t actually play out in your backyard, but it takes place in graphene because of its high “elastic modulus” – a material property that means any vibrations will cause large changes to the membrane’s tension.

In applying this concept, the group fabricated graphene “drums” with diameters ranging from 5 to 20 micrometers (1 million micrometers = 1 meter). Those drums can be set in motion either by an alternating electric field or by the random thermal vibrations of their constituent atoms (the same atomic vibrations that define an object’s temperature); the movement is detected through laser interferometry, a method devised several years ago at Cornell in Harold Craighead’s group. Craighead is the Charles W. Lake Jr. Professor of Engineering and a collaborator on this work.

External voltage applied to the graphene membrane acts as a sort of “tuning peg” to control the membrane tension and engineer the coupling needed to control one oscillation mode by exciting the other.

“We’ve shown that there is an effect that will convert energy from one mechanical mode to another mechanical mode,” De Alba said. “It allows us to either damp out or amplify vibrations of one mode by activating the other mode.”

“You’re able to change the fundamental frequency of this object’s motion … essentially its thermal motion, by simply applying voltage,” Parpia said.

The term “phonon cavity” was chosen, De Alba said, because the mechanical effect is similar to that of an optical cavity, which can be used to convert energy from laser light into mechanical motion. Phonons are quasi-particles used to describe vibrations in the same way that photons are particles of light.

This discovery paves the way for the application of graphene mechanical resonators in telecommunication applications – for instance, as frequency mixers.

“And because graphene is only a single atom thick, it has such a low mass that it makes a very good force sensor, gas sensor or pressure sensor,” De Alba said. “It could be used in research labs to study ultra-weak forces.”

In addition, when cooled to near absolute zero, these resonators can play a key role in detection of the faintest quantum signals and in identifying and developing new, secure telecommunication technologies.

Read more at: http://phys.org/news/2016-06-graphene-frequency-mixer.html#jCp

 

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June 2016: New high-capability solid-state electron microscope detector enables novel studies of materials

At Cornell University, the Sol M. Gruner (SMG) detector group has developed and demonstrated a new type of imaging electron detector that records an image frame in 1/1000 of a second, and can detect from 1 to 1,000,000 electrons per pixel. This is 1000 times the intensity range, and 100 times the speed of conventional electron microscope image sensors.

Capture of all the transmitted electrons allows quantitative measurement of materials properties, such as internal electric and magnetic fields, which are important for use of the materials in memory and electronics applications.

Cornell University researchers developed and tested a new for electron microscopes that enables quantitative measurements of electric and magnetic fields from micrometers down to atomic resolution. The device is an adaptation of existing solid-state X-ray detector technology, now modified to function as a high-speed, high electron diffraction camera. Dynamic range denotes the maximum range of signals that can be detected by a pixel. The resulting electron microscope pixel array detector records an image frame in under a millisecond, and can detect from 1 to 1,000,000 primary electrons per pixel per image frame. This is 1000 times the dynamic range, and 100 times the speed of conventional electron image sensors. These properties allow us to record the entire unsaturated diffraction pattern in scanning mode, and simultaneously capture bright field, dark field, and phase contrast information, as well as analyze the full scattering distribution, opening the way for new multichannel imaging modes.

Read more at: http://phys.org/news/2016-06-high-capability-solid-state-electron-microscope-detector.html#jCp

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May 2016: Electrical properties of superconductor altered by ‘stretching’

In the early 1970s, in the basement of Clark Hall, the Cornell team of professors David Lee and Robert Richardson, along with then-graduate student Douglas Osheroff, first observed superfluid helium-3. For that breakthrough, the catalyst for further research into low-temperature physics, the trio was awarded the 1996 Nobel Prize in physics.

Twenty years later, another Cornell-led team – working in that same building – has made an important discovery regarding the superconductor strontium ruthenate (Sr2RuO4,or SRO), often described as a crystalline analog of superfluid helium-3. What ties them together is the unusual way the electrons are paired together in SRO, and how the helium atoms are paired in the superfluid. That quality makes SRO intriguing for possible applications in quantum computation.

A team led by Kyle Shen, associate professor of physics, and Darrell Schlom, the Herbert Fisk Johnson Professor of Industrial Chemistry, both members of the Kavli Institute for Nanoscale Science at Cornell, has shown the ability to alter the electrical properties of the unique material through the application of strain – stretching thin films of SRO on top of a single-crystal substrate.

Read More

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May 2016: A Pioneer of Scientific Tools Sol Gruner, known for developing x-ray detectors, is a toolmaker, tackling scientific problems and exploring the unknown

by Jackie Swift

“Most scientists focus on a very specific area, but I do many different things,” says Sol Gruner, Physics. “I’m a research mutt. Mainly, I develop tools to attack scientific problems people haven’t looked at yet, largely because the tools needed to solve those problems haven’t existed.”

Gruner’s tool-making expertise has resulted in an array of scientific breakthroughs and developments over the years. One area of research he is well-known for involves the development of new kinds of x-ray detectors for use at synchrotron facilities. X-ray detectors are crucial tools that use x-ray fraction to examine how materials change during experiments, and for several decades, Gruner’s has been one of the foremost groups working in this field. Sol Gruner, known for developing x-ray detectors, is a toolmaker for tackling scientific problems and exploring the unknown.

The Gruner group developed the first pixel array detectors (PADs)—which directly capture x-rays and process the resultant signals in integrated circuit chips—for use in very fast, time-resolved synchrotron science experiments, both at storage ring sources, such as the Cornell High Energy Synchrotron Sources (CHESS), and at x-ray free electron lasers. For example, his group designed the detectors in use at the Linac Coherent Light Source, the world’s first high-energy x-ray free electron laser now operating near Stanford University in California. They allow researchers to look at matter in time scales of femtoseconds (one millionth of one billionth of a second).

– See more at: https://research.cornell.edu/news-features/pioneer-scientific-tools#sthash.tb7udSmM.dpuf

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