Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Wandering heat: Anomalous heat distribution in one-dimensional systems

12.02.2014
According to Fourier’s law, heat spreads evenly throughout a system. For two- and one-dimensional objects such as films or the finest of wires, however, other rules seem to apply. NIM scientists have now pinned these down.

Just as ember spreads through a piece of coal, heat principally diffuses at a constant rate. The corresponding physical law known as Fourier’s law was already established 200 years ago.


Uniform spreading of heat ceases in low dimensions

Later, scientists came to the conclusion that other rules must apply to the distribution of heat in two- or one-dimensional objects such as films or very fine wires. Respective evidence was provided, for example, by experiments with carbon nanotubes or organic molecular chains, where thermal conductivity was not only dependent on the object’s material but also on its size, or rather its length.

This means that in some materials thermal conductivity increases with the object’s length, while in others it decreases. However, no one has so far been able to derive a physical law similar to Fourier’s law from these observations.

Together with international colleagues, NIM physicist Prof. Peter Hänggi (University of Augsburg) and his team have now gone one step further in the quest for such a law. The scientists have for the first time established a universally valid mathematical connection between object-size-dependent thermal conductivity and the corresponding anomalous rate of heat diffusion.

The insights thus gained allow scientists to devise hybrid materials which display entirely new thermal properties in one- or two-dimensional form. They exploit the fact that in these cases the rate of heat diffusion can be very high in some material compositions and extremely low in others. This is to say that one material allows heat to travel through it very quickly, while another functions as thermal insulator. The theoretical calculations are of particular interest for objects at nanoscale, whose thermal behavior is hard to measure in experiments. Currently, nanostructures composed of carbon materials which are to serve as phononic diodes or heat storage systems (memory) are simulated by computer models. Analogous to electronic components, these elements can then be used to conduct information processing.

“The exploration of heat diffusion in low-scale dimensions is only just beginning and certainly holds many surprises – as well as a huge potential”, explains Peter Hänggi. “The ubiquitous detrimental thermal losses, for example, can be used to beneficial effect for functional materials or phononic information processing. Maybe, in the distant future, the dream of a computer functioning with waste heat will come true.”

Publication:

Anomalous Heat Diffusion by Sha Liu, Peter Hänggi, Nianbei Li, Jie Ren, and Baowen Li. Phys. Rev. Lett. 112: 040601 (2014)

http://prl.aps.org/abstract/PRL/v112/i4/e040601

Contact person:

Prof. Peter Hänggi
Chair of Theoretical Physics I
Institute of Physics
University of Augsburg
86135 Augsburg, Germany
Tel: +49 821 598-3250
Hanggi@physik.uni-augsburg.de

Klaus P. Prem | idw
Further information:
http://www.nano-initiative-munich.de
http://www.uni-augsburg.de

More articles from Physics and Astronomy:

nachricht Active pits on Rosetta’s comet
03.07.2015 | Max Planck Institute for Solar System Research, Göttingen

nachricht Researchers find the macroscopic Brownian motion phenomena of self-powered liquid metal motors
02.07.2015 | Science China Press

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Viaducts with wind turbines, the new renewable energy source

Wind turbines could be installed under some of the biggest bridges on the road network to produce electricity. So it is confirmed by calculations carried out by a European researchers team, that have taken a viaduct in the Canary Islands as a reference. This concept could be applied in heavily built-up territories or natural areas with new constructions limitations.

The Juncal Viaduct, in Gran Canaria, has served as a reference for Spanish and British researchers to verify that the wind blowing between the pillars on this...

Im Focus: X-rays and electrons join forces to map catalytic reactions in real-time

New technique combines electron microscopy and synchrotron X-rays to track chemical reactions under real operating conditions

A new technique pioneered at the U.S. Department of Energy's Brookhaven National Laboratory reveals atomic-scale changes during catalytic reactions in real...

Im Focus: Iron: A biological element?

Think of an object made of iron: An I-beam, a car frame, a nail. Now imagine that half of the iron in that object owes its existence to bacteria living two and a half billion years ago.

Think of an object made of iron: An I-beam, a car frame, a nail. Now imagine that half of the iron in that object owes its existence to bacteria living two and...

Im Focus: Thousands of Droplets for Diagnostics

Researchers develop new method enabling DNA molecules to be counted in just 30 minutes

A team of scientists including PhD student Friedrich Schuler from the Laboratory of MEMS Applications at the Department of Microsystems Engineering (IMTEK) of...

Im Focus: Bionic eye clinical trial results show long-term safety, efficacy vision-restoring implant

Patients using Argus II experienced significant improvement in visual function and quality of life

The three-year clinical trial results of the retinal implant popularly known as the "bionic eye," have proven the long-term efficacy, safety and reliability of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

World Conference on Regenerative Medicine in Leipzig: Last chance to submit abstracts until 2 July

25.06.2015 | Event News

World Conference on Regenerative Medicine: Abstract Submission has been extended to 24 June

16.06.2015 | Event News

MUSE hosting Europe’s largest science communication conference

11.06.2015 | Event News

 
Latest News

Siemens receives order for offshore wind power plant in Great Britain

03.07.2015 | Press release

'Déjà vu all over again:' Research shows 'mulch fungus' causes turfgrass disease

03.07.2015 | Agricultural and Forestry Science

Discovery points to a new path toward a universal flu vaccine

03.07.2015 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>