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Light-Controlled Self-Assembly of Semiconductor Nanoparticles into Twisted Ribbons

The collective properties of nanoparticles manifest in their ability to self-organize into complex microscale structures. Slow oxidation of tellurium ions in cadmium telluride (CdTe) nanoparticles results in the assembly of 1- to 4-micrometer-long flat ribbons made of several layers of individual cadmium sulfide (CdS)/CdTe nanocrystals. Twisting of the ribbons with an equal distribution of left and right helices was induced by illumination with visible light. The pitch lengths (250 to 1500 nanometers) varied with illumination dose, and the twisting was associated with the relief of mechanical shear stress in assembled ribbons caused by photooxidation of CdS. Unusual shapes of multiparticle assemblies, such as ellipsoidal clouds, dog-bone agglomerates, and ribbon bunches, were observed as intermediate stages. Computer simulations revealed that the balance between attraction and electrostatic repulsion determines the resulting geometry and dimensionality of the nanoparticle assemblies.

1 posted on 03/25/2010 10:57:48 AM PDT by neverdem
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To: neverdem

Ohhh. So all that crazy talk about miracles from the Light of the World is...

never mind.

Science and religion are very very seperate. Mya bad.


2 posted on 03/25/2010 10:59:54 AM PDT by Voter62vb
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To: neverdem; SunkenCiv; KevinDavis

interesting


3 posted on 03/25/2010 11:00:51 AM PDT by GeronL (All politicians are POS. Some are just piled higher and smell worse.)
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To: Revolting cat!

Is it true that dark is heavier than light and that’s why it sinks to the bottom of the ocean?


4 posted on 03/25/2010 11:02:26 AM PDT by a fool in paradise (VP Biden on Obamacare's passage: "This is a big f-ing deal". grumpygresh: "Repeal the f-ing deal")
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To: Revolting cat!

5 posted on 03/25/2010 11:03:06 AM PDT by a fool in paradise (VP Biden on Obamacare's passage: "This is a big f-ing deal". grumpygresh: "Repeal the f-ing deal")
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To: neverdem

This was poorly written. They might as well have said that “light can affect matter”. Big deal. In this case, light can cause an electrochemical change in matter. Been doing it in plants for a long time.


6 posted on 03/25/2010 11:08:49 AM PDT by yefragetuwrabrumuy
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To: neverdem

I see matter as nothing more than, metaphorically speaking, coagulated energy. I also think that an excellent analogy to our “real world” would be “The Matrix”. What we perceive as the “real world” is almost entirely empty space.

That is significant.


7 posted on 03/25/2010 11:09:31 AM PDT by RobRoy (The US today: Revelation 18:4)
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To: neverdem

Learned this at age 5 when I left an old 45rpm on the window sill.


8 posted on 03/25/2010 11:09:49 AM PDT by 668 - Neighbor of the Beast (STOP the Tyrananny State.)
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To: neverdem

Light is a bunch of photons zipping through space at, well, the speed of light. Even though their mass is miniscule, the fact that they beat the hell out of something after a while should really not be a surprise.

Or am I missing something?


10 posted on 03/25/2010 11:14:25 AM PDT by Vermont Lt (This nation, of the people, by the people, and for the people has perished from the land.)
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To: neverdem

/


12 posted on 03/25/2010 11:16:12 AM PDT by happinesswithoutpeace (1.416785(71) x 10^32)
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To: neverdem

what happened to nanoparticles not exposed to ambient light?


14 posted on 03/25/2010 11:33:32 AM PDT by stuckinloozeeana
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To: neverdem
After 72 hours of exposure to ambient light, strands of nanoparticles twisted and bunched together.


17 posted on 03/25/2010 11:37:11 AM PDT by Hot Tabasco
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To: neverdem
The surface of the nanoparticles in this experiment were made of cadmium sulfide. To begin with, they had a slightly negative electromagnetic charge. But when photons, or particles of light, hit the nanoparticles, their energy excited electrons on the nanoparticles, causing chemical reactions that made them even more negatively charged.

If I'm remembering correctly back in the mid to late 60's photocell operated relays were fabricated from cadmium sulfide as the photo sensitive element used to control the relay operation. I seem to recall selenium also have photo sensitive properties. Selenium was mainly used in "solid state" rectifiers to produce DC from AC input without resorting to vacuum tubes or mercury filled "ignitrons". This technology was in use before WWII and most contemporary EE have never even heard of it.

Regards,
GtG

24 posted on 03/25/2010 2:21:02 PM PDT by Gandalf_The_Gray (I live in my own little world, I like it 'cuz they know me here.)
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To: El Gato; Ernest_at_the_Beach; Robert A. Cook, PE; lepton; LadyDoc; jb6; tiamat; PGalt; Dianna; ...
How Zebrafish Mend a Broken Heart

Research Offers Clue Into How Hearts Can Regenerate in Some Species

New test takes guesswork out of diagnosing early-stage Alzheimer's disease

Memory decline linked to an inability to ignore distractions

FReepmail me if you want on or off my health and science ping list.

25 posted on 03/25/2010 3:11:57 PM PDT by neverdem (Xin loi minh oi)
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To: your local physicist; The_Reader_David; snarks_when_bored; Fred Nerks; FredZarguna; Billthedrill; ..
Like, WAY COOL *PING*, dudes.

Cheers!

31 posted on 03/25/2010 10:16:10 PM PDT by grey_whiskers (The opinions are solely those of the author and are subject to change without notice.)
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