Sunday Observer Online
   

Home

Sunday, 20 November 2011

Untitled-1

observer
 ONLINE


OTHER PUBLICATIONS


OTHER LINKS

Marriage Proposals
Classified
Government Gazette

Nano car has molecular 4-wheel drive: Smallest electric car in the world

Reduced to the max: the emission-free, noiseless 4-wheel drive car, jointly developed by Empa researchers and their Dutch colleagues, represents lightweight construction at its most extreme.

The nano car consists of just a single molecule and travels on four electrically-driven wheels in an almost straight line over a copper surface. The “prototype” can be admired on the cover of the latest edition of Nature.

To carry out mechanical work, one usually turns to engines, which transform chemical, thermal or electrical energy into kinetic energy in order to, say, transport goods from A to B. Nature does the same thing; in cells, so-called motor proteins such as kinesin and the muscle protein actin carry out this task. Usually they glide along other proteins, similar to a train on rails, and in the process “burn” ATP (adenosine triphosphate), the chemical fuel, so to speak, of the living world. A number of chemists aim to use similar principles and concepts to design molecular transport machines, which could then carry out specific tasks on the nano scale. According to an article in the latest edition of science magazine “Nature,” scientists at the University of Groningen and at Empa have successfully taken “a decisive step on the road to artificial nano-scale transport systems.” They have synthesised a molecule from four rotating motor units, i.e. wheels, which can travel straight ahead in a controlled manner. “To do this, our car needs neither rails nor petrol; it runs on electricity.

It must be the smallest electric car in the world and it even comes with 4-wheel drive” comments Empa researcher Karl-Heinz Ernst. Range per tank of fuel: still room for improvement The downside: the small car, which measures approximately 4x2 nanometres about one billion times smaller than a VW Golf needs to be refuelled with electricity after every half revolution of the wheels via the tip of a scanning tunnelling microscope (STM). Furthermore, due to their molecular design, the wheels can only turn in one direction.

“In other words: there’s no reverse gear,” says Ernst, who is also a professor at the University of Zurich, laconically. According to its “construction plan” the drive of the complex organic molecule functions as follows: after sublimating it onto a copper surface and positioning an STM tip over it leaving a reasonable gap, Ernst’s colleague, Manfred Parschau, applied a voltage of at least 500 mV. Now electrons should “tunnel” through the molecule, thereby triggering reversible structural changes in each of the four motor units. It begins with a cis-trans isomerisation taking place at a double bond, a kind of rearrangement in an extremely unfavourable position in spatial terms, though, in which large side groups fight for space.

As a result, the two side groups tilt to get past each other and end up back in their energetically more favourable original position the wheel has completed a half turn.

If all four wheels turn at the same time, the car should travel forwards. At least, according to theory based on the molecular structure.

To drive or not to drive a simple question of orientation And this is what Ernst and Parschau observed: after ten STM stimulations, the molecule had moved six nanometres forwards in a more or less straight line.

“The deviations from the predicted trajectory result from the fact that it is not at all a trivial matter to stimulate all four motor units at the same time,” explains “test driver” Ernst.

ScienceDaily

 

EMAIL |   PRINTABLE VIEW | FEEDBACK

Donate Now | defence.lk
www.apiwenuwenapi.co.uk
LANKAPUVATH - National News Agency of Sri Lanka
Telecommunications Regulatory Commission of Sri Lanka (TRCSL)
www.army.lk
www.news.lk
www.defence.lk
 

| News | Editorial | Finance | Features | Political | Security | Sports | Spectrum | Montage | Impact | World | Obituaries | Junior | Magazine |

 
 

Produced by Lake House Copyright © 2011 The Associated Newspapers of Ceylon Ltd.

Comments and suggestions to : Web Editor