Science Fiction
Dictionary
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
 |
Shape-Changing Metal Antenna
Researchers at Utah and North Carolina have created a controllable metal antenna that can change its shape, and thus the frequency at which it resonates, on demand.
(Shape-Changing Metal Antenna)
To fabricate the antenna, the researchers injected a conductive, low-viscosity metal alloy (eutectic gallium indium, or EGaIn) into a 51-mm-long microchannel that is divided into four segments. Two rows of posts placed perpendicular to the channel divide the inner and outer segments of the antenna. A thin, membrane-like solid oxide skin spontaneously forms on the metal surface that mechanically stabilizes the metal at the posts, preventing metal in adjacent segments from merging. The liquid metal remains stable as long as its surface oxide is not ruptured.At a length of 25 mm, the initial dipole antenna state, defined by the two inner segments, represents the shortest of three possible states. As the shortest antenna, it also has the highest frequency. In order to elongate the antenna, and thus decrease its frequency, the researchers applied a critical pressure on the liquid metal at one segment boundary. This critical pressure ruptures the oxide skin and squirts the metal between the posts to merge with one of the outermost metal segments. This process increases the length of the antenna and creates a second state at a lower frequency than the first state. By controlling the spacing between the posts, the researchers could control the pressure at which the oxide ruptures.
To achieve the third state – the one with the longest length and lowest frequency – the researchers ruptured the skin on the other side of the antenna, allowing the liquid metal in the inner segment to merge with the other outer segment. Once the skin is ruptured, the metal flows extremely quickly – in a few milliseconds – due to its low viscosity and the short distance it has to travel.
In his 1942 novella Waldo, Heinlein draws on the idea of broadcast power. The aircars (including the amazing broomstick speedster) use standard, rigid antennas to draw power.
As the story progresses, the deKalb antennas mysteriously fail to function. When one of them is fixed by a "hex doctor", engineers go to investigate.
"What!" put in Stevens. "You don't mean to stand there and tell me an old witch doctor fixed your deKalbs.""Not witch doctor - hex doctor..."
The skycar looked quite ordinary. Stevens examined the deKalbs and saw some faint chalk marks on their metal sides... "Watch while I cut in reception."
Stevens waited, heard the faint hum as the circuits became activized and looked.
The antennae of the deKalbs, each a rigid pencil or metal, were bending, flexing, writhing like a cluster of worms. They were reaching out, like fingers...
(Read more about Heinlein's broadcast power receptors)
From Physorg.
Scroll down for more stories in the same category. (Story submitted 7/31/2011)
Follow this kind of news @Technovelgy.| Email | RSS | Blog It | Stumble | del.icio.us | Digg | Reddit |
Would
you like to contribute a story tip?
It's easy:
Get the URL of the story, and the related sf author, and add
it here.
Comment/Join discussion ( 0 )
Related News Stories - (" Engineering ")
Vipera Electric Skis From Frigid Dynamics
'JOAN strapped on her power-skis...' - Ursula K. Le Guin, 1964.
Pivotal Blackfly Electric Aircraft Lifts And Hovers
'That explains how it was so easy for me to remain motionless in midair...' - RH Roman, 1929.
Tiny Flying Robot Weighs Just One Gram
'Aerostat meant anything that hung in the air. This was an easy trick to pull off nowadays.' - Neal Stephenson, 1995.
Some Ringworld Configurations Are Stable
'The Ringworld had no horizon. There was no line where the land curved away from the sky.'
Technovelgy (that's tech-novel-gee!) is devoted to the creative science inventions and ideas of sf authors. Look for the Invention Category that interests you, the Glossary, the Invention Timeline, or see what's New.
Science Fiction
Timeline
1600-1899
1900-1939
1940's 1950's
1960's 1970's
1980's 1990's
2000's 2010's
Current News
Robot Hand Creeps Along, Separate From It's Owner
'The crawling... object was V-Stephen's surgeon-hand...'
Taikonauts Exercise In China's Tiangong Space Station
'Joe got out the gravity-simulator harnesses...'
Korean Exoskeleton Suit F1 Helps You Put It On
'Better late than never.'
Have AI Researchers Given Up On 'Bio-Babies'?
'You couldn't have the capstone without the pyramid to hold it up.'
Bunker Busters and Bore-Pellets
'The first revelation of the new Soviet bore-pellets.'
'Spikeless' Brand Swizzle Stick Detects Spiked Drinks
'the unobtrusive inspections with tiny remote-cast snoopers...'
Heart Patches Grown In The Lab Repair Hearts
I'm hoping that this procedure becomes a normal part of medical practice!
Humanoid Robots Spotted In Homes Performing Household Chores
'... nothing was perfected until M. Pantalon announced the completion of his automatic valet.'
Musk Proposes Sites For Martian Cities
'...its streets were of remarkable width, with few or no buildings so high as mosques, churches, State-offices, or palaces in Tellurian cities.'
Bambot Open Source Cheap Delivery Robot
'Not since the time he rewired the delivery robot...'
Robot Collective Acts Like A Smart Material
'...it was all composed of tiny, identical cubes, carefully laid to form a tilelike surface.'
Vipera Electric Skis From Frigid Dynamics
'JOAN strapped on her power-skis...'
Pixel Watch 'Loss of Pulse Detection' And Philip K. Dick
'He carried on his person a triggering mechanism sensitive to his heartbeat.'
Nuclear Plant Restarted To Power AI To Feed Us Dreams
'...Anything was possible in my imaginary environment.'
SpaceX's Starman Tesla Roadster In Space
'Somewhere in space, a chrome and blue automobile raced the green light of Earth.'
Pivotal Blackfly Electric Aircraft Lifts And Hovers
'That explains how it was so easy for me to remain motionless in midair...'
