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David A Muller

@davidamuller.bsky.social
450 followers 516 following 142 posts

"Learning more and more about less and less" Materials Physics and Electron Microscopy at Cornell (he/him) muller.research.engineering.cornell…

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David A Muller @davidamuller.bsky.social · 15/07/2026
Very closely related to beam emittance in accelerator physics (it’s the phase space along x,y or z, and the key source metric everyone over here at the Center for Bright Beams tries to optimize), but emittance means something very different in optics!
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David A Muller @davidamuller.bsky.social · 24/06/2026
Michael Zachman gave a talk today at the BNL Cryo workshop showing how her work on Li-H that at the time had been treated skeptically because no-one had ever seen anything like it before, today is both verified and accepted as the conventional wisdom
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David A Muller @davidamuller.bsky.social · 15/06/2026
And in the sequel it's CO2
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David A Muller @davidamuller.bsky.social · 06/06/2026
Seeing Li ions at atomic resolution is hard, seeing the missing ones? Harder. Dasol's electron ptychography now images Li vacancies in a battery cathode in 3D—atom column by atom column: pubs.acs.org/doi/10.1021/... @pubs.acs.org 🧪⚛️
pubs.acs.org
Atomic-Scale Imaging of Lithium Vacancies in a Battery Cathode by Multislice Electron Ptychography
Atomic-resolution imaging of battery materials is critical for identification of local defects and structural variations, which are tied to battery performance. However, since battery materials are, b...
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David A Muller @davidamuller.bsky.social · 21/05/2026
Cornell's cows are absolutely out standing in their fields right now (all 2,000+ acres). Maybe the NYT just forgot we are an ivy again?
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David A Muller @davidamuller.bsky.social · 04/04/2026
I would have said it went to a nice farm upstate with lots of room to run samples, but that’s where it was. It is now at UW Seattle
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David A Muller @davidamuller.bsky.social · 02/04/2026
The concept that STEM is reciprocal to TEM is easier to explain with a Nion Column
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David A Muller @davidamuller.bsky.social · 01/04/2026
The real version is just as funny: “In Afrikaans, the term for a porcupine is ystervark (iron pig)”
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David A Muller @davidamuller.bsky.social · 01/04/2026
With a DED the 4D-data set might even be quantitative in the intensities. If so, crystal structure, Debye Waller factors and maybe even bonding info would be possible. Collect EDX at the same time as rocking the beam, and site occupancy from ALCHEMI would work. Jim Zuo would know the theory
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David A Muller @davidamuller.bsky.social · 31/03/2026
almost Ultra-LARBED!
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Reposted by David A Muller
Cornell Center for Materials Research (CCMR) @cornellccmr.bsky.social · 26/03/2026
Atomic‑scale nickel. Zero precious metals. Serious fuel‑cell power—thanks in part to CCMR tools news.cornell.edu/stories/2026...
news.cornell.edu
Nickel catalyst enables high-performance fuel cell free of precious metals | Cornell Chronicle
Cornell researchers have developed a non-precious-metal catalyst that represents a major step toward alkaline fuel cells that use inexpensive commodity metals, such as nickel and cobalt, in several en...
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David A Muller @davidamuller.bsky.social · 12/03/2026
@sciencex.bsky.social ex.bsky.social picked up our #ptychography paper on imaging the atomic-scale roughness in transistor channels in 3D, in a single scan and without having to tilt the sample. ⚛️
ex.bsky.social
Bluesky
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Reposted by David A Muller
Katharine Hayhoe @katharinehayhoe.com · 13/02/2026
Bluesky is the new science Twitter, new study by @whysharksmatter.bsky.social and Julia Wester concludes! "Results show that for every reported professional benefit that scientists once gained from Twitter, scientists can now gain that benefit more effectively on Bluesky than on Twitter."
academic.oup.com
Scientists no Longer Find Twitter Professionally Useful, and have Switched to Bluesky
Synopsis. Social media has become widely used by the scientific community for a variety of professional uses, including networking and public outreach. For
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David A Muller @davidamuller.bsky.social · 11/02/2026
The published version is here: www.nature.com/articles/s41...
nature.com
Dose-efficient cryo-electron microscopy for thick samples using tilt- corrected scanning transmission electron microscopy - Nature Methods
Tilt-corrected bright-field scanning transmission electron microscopy offers enhanced cryogenic electron microscopy contrast and substantial improvement in dose efficiency for thick samples such as ba...
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David A Muller @davidamuller.bsky.social · 11/02/2026
The offical citation is "For developing a new generation of electron detectors and reconstruction algorithms leading to the highest resolution electron microscope." www.nae.edu/345149/NAENe... or as a friend joked "the academy award goes to David for the best picture" 🧪 ⚛️ #NAE
nae.edu
National Academy of Engineering Elects 130 Members and 28 International Members
The National Academy of Engineering (NAE) today announced the election of 130 members and 28 international members to its Class of 2026, said NAE President ...
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David A Muller @davidamuller.bsky.social · 25/01/2026
Pretty sure they’d be negative
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David A Muller @davidamuller.bsky.social · 25/01/2026
Yes, these would be the local conditions where the nucleation and growth occurs, so mainly in the clouds. Can also be modeled in a lab doi.org/10.48550/arX...
doi.org
Toward a Comprehensive Model of Snow Crystal Growth Dynamics: 1. Overarching Features and Physical Origins
We describe a comprehensive model for the formation and morphological development of atmospheric ice crystals growing from water vapor, also known as snow crystals. Our model derives in part from empi...
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David A Muller @davidamuller.bsky.social · 25/01/2026
Saturation is 100% relative humidity. Supersaturation is the amount of water vapor in the air above 100% RH. This excess is not stable and will precipitate out - so here it basically measures how fast the snowdrops will form
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David A Muller @davidamuller.bsky.social · 25/01/2026
Saturation is 100% relative humidity. Supersaturation is the amount of water vapor in the air above 100% RH. This excess is not stable and will precipitate out - so here it measures how much/how fast the snowdrops will form
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David A Muller @davidamuller.bsky.social · 25/01/2026
Given the weather today, it’s time to repost my favorite phase diagram: Nakaya’s snow crystal morphology. We are towards the bottom right today. 🧪 ⚛️ #cryoEM
Phase diagram for shapes of snowflakes as a function of temperature and water vapor content, showing when to expect fluffy snowflakes and dense crumbly bits of ice
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David A Muller @davidamuller.bsky.social · 21/01/2026
Faint purple and green aurora
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David A Muller @davidamuller.bsky.social · 30/12/2025
And this is when Bluesky became the old twitter
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David A Muller @davidamuller.bsky.social · 27/12/2025
Measurement of a Quantum of Solace
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David A Muller @davidamuller.bsky.social · 11/12/2025
Yes, I think Hillier was hired by RCA to commercialize his electron microscope. I remember meeting him as a grad student when he came up to Cornell to visit John Silcox in the early 90’s
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David A Muller @davidamuller.bsky.social · 10/12/2025
and @joachim123.bsky.social was very briefly a postdoc (one of 3 labs he worked in during his fellowship in the US)
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David A Muller @davidamuller.bsky.social · 10/12/2025
That would be Ben Siegel. He joined Cornell in 1948, after having worked on the Manhattan project looking at diffusion membranes with TEM. James Hillier (then at RCA) donated an RCA TEM to Cornell, and found funding for student fellowships. Ken Downing did his PhD with Ben, as did Earl Kirkland
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David A Muller @davidamuller.bsky.social · 29/11/2025
I’ll be teaching the Hall effect in solid state this Tuesday. Let’s see if I can sneak it in
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David A Muller @davidamuller.bsky.social · 12/11/2025
Time to break it up when they dosey do
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David A Muller @davidamuller.bsky.social · 10/11/2025
While Cornell has field theorists, we also have practitioners
Three horse are out standing in their field at the Cornell horse farm, with strong fall colors on the trees behind them
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David A Muller @davidamuller.bsky.social · 20/10/2025
The scale of the room doesn’t come across that clearly in the picture. The cones on the wall are six feet deep to absorb long wavelength waves, and the entry in on the 2nd floor of the building with a full floor of empty space below the mesh you walk in on - not for those with a fear of heights!
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David A Muller @davidamuller.bsky.social · 10/10/2025
Imaging hydrogen atoms with ptychography
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David A Muller @davidamuller.bsky.social · 09/10/2025
Our microscope lab was in the same buliding as the anechoic chamber - in one of the old varechoic rooms. The acoustics folks showed us how to get things quiet.
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David A Muller @davidamuller.bsky.social · 08/10/2025
Jim West's group taught us everything we know about building ultra-quiet rooms
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David A Muller @davidamuller.bsky.social · 08/10/2025
Ducktober
Two wood ducks paddling together in Cayuga lake as the trees on the opposite shore are just starting to turn
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David A Muller @davidamuller.bsky.social · 07/10/2025
Astro folks might want a turn?
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David A Muller @davidamuller.bsky.social · 24/09/2025
#cryoEM 🧪⚛️ Lena’s paper on imaging thick biological sections with STEM is finally published! We started this work almost 10 years ago. After Lena passed in 2023, I spent much of my sabbatical working with Yue and Steve to wrap this up. Also learned a lot about TEM vs STEM dose efficiency
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David A Muller @davidamuller.bsky.social · 28/08/2025
Some good news 🧪⚛️
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David A Muller @davidamuller.bsky.social · 05/08/2025
We had 35 participants at our summer school a few weeks ago testing this on their laptops. Turns out a Macbook M4 pro is almost as fast as a 10GB slice of an A100. From the school, here is a 1-hour reconstruction. (Data took a few seconds to record at the school in a crowded scope room)
Electron ptychography 3D reconstruction of SiC after 100 iterations, taking 1 hour.  This is an animated depth section showing the depth slicing through a thin SiC film and its interface with an amorphous layer.  A small hole drilled with a parked electron beam is visible in the top half of the image
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David A Muller @davidamuller.bsky.social · 05/08/2025
Our new zippy ptychography code, PtyRAD is now out in print. 3D Multislice reconstructions that used to take a day, now can be done in about an hour! 🧪⚛️ #ptycho paper and install links: academic.oup.com/mam/article/...
academic.oup.com
PtyRAD: A High-Performance and Flexible Ptychographic Reconstruction Framework with Automatic Differentiation
Abstract. Electron ptychography has recently achieved unprecedented resolution, offering valuable insights across diverse material systems, including in th
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David A Muller @davidamuller.bsky.social · 04/08/2025
Good use case for comic sans
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David A Muller @davidamuller.bsky.social · 02/08/2025
I don't know how many were posters. Overall probably a 10-15% drop. For cancelled invited talks it felt larger, or perhaps it was that my area had a lot of invited talks from China, reflecting the huge investments and activity there on this topic
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David A Muller @davidamuller.bsky.social · 01/08/2025
I’m told we had about 200 cancelled talks due to visa problems or US funding cuts. We were told not to travel, but have travel funds that will vanish if we don’t, so the whole gang was here
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David A Muller @davidamuller.bsky.social · 26/07/2025
Given the location, we know he didn’t simply walk
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David A Muller @davidamuller.bsky.social · 21/07/2025
That earned a follow
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David A Muller @davidamuller.bsky.social · 13/07/2025
Actually the original 3 make sense to watch after Andor. There are no others
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David A Muller @davidamuller.bsky.social · 13/07/2025
media.tenor.com
a man with a red face is standing in a space ship and saying it 's a trap .
Alt: Admiral Akbar saying it 's a trap .
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David A Muller @davidamuller.bsky.social · 08/07/2025
Our hands-on workshop on Electron #Ptychography ! ⚛️🧪 using our new fast python code starts tomorrow, Tuesday, July 8. Lecture Schedule is below, for folks who want to listen in on-line. We hope to post the tutorial and code walk through videos later. cornell.zoom.us/j/9512638476...
Schedule of lectures for the ptychography workshop, from 8-11 July
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Reposted by David A Muller
"Online Rent-a-Sage" Bret Devereaux @bretdevereaux.bsky.social · 04/07/2025
This is fantastic, do read it.
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David A Muller @davidamuller.bsky.social · 02/07/2025
Canandaigua for ice cream, Watkins Glenn for boat tours
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David A Muller @davidamuller.bsky.social · 01/07/2025
Took a break and conducted some pier review last week. 12/10
Seneca lake pier at Watkins glenCanandaiga lake pier at sunset.  It has lots of little boat sheds
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