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From: Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>
Newsgroups: sci.electronics.design
Subject: Re: Strings that can vibrate forever (almost)
Date: Sat, 25 May 2024 11:25:04 -0000 (UTC)
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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