Re: Strings that can vibrate forever (almost)

Jeroen Belleman <jeroen@nospam.please> wrote:

On 5/25/24 07:04, Jan Panteltje wrote:

On a sunny day (Thu, 23 May 2024 11:04:02 +0200) it happened Jeroen Belleman
<jeroen@nospam.please> wrote in <v2n0m9$1m371$2@dont-email.me>:
 

On 5/23/24 07:08, Jan Panteltje wrote:

Strings that can vibrate forever (kind of)
https://www.sciencedaily.com/releases/2024/05/240522130402.htm
Source:
Delft University of Technology
Summary:
Researchers have engineered string-like resonators capable of
vibrating longer at ambient temperature
than any previously known solid-state object -- approaching what is
currently only achievable near absolute zero
temperatures.
Their study pushes the edge of nanotechnology and machine learning to
make some of the world's most sensitive mechanical
sensors.
 
Interesting for inertial navigation!
 
Mechanical 214 kHz resonator with a Q of 6.6 billion at room temperature
see paper:
https://www.nature.com/articles/s41467-024-48183-7
figure 4
 

 
Interesting, indeed, but this looks *very* fragile!

 
Yes, but maybe not enough free space to move so much it breaks?

 
As I understand it, if a string touches something, it tends to stick.
That was one of the problems that caused low yields in early devices.
 

 
I just hope they used a Faraday cage and kept it away from other sources
and their harmonics in the 214 kHz range.
Wallwarts! bats? some other piezo stuff.

 
With a Q > 1e9, coupling to outside influences is by definition
very weak. I don't see this thing becoming important as a low
noise oscillator element though. Pity. Maybe it's useful as a
precision thermometer.
 
Jeroen Belleman
 

Possibly some sort of sensor.

Because the oscillation obeys a differential equation, while it takes Q
cycles to respond to external forcing,it responds instantly to any effect
that changes the mass or spring constant.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs  Principal Consultant  ElectroOptical Innovations LLC /
Hobbs ElectroOptics  Optics, Electro-optics, Photonics, Analog Electronics