For years, scientists have labored to reproduce this feat(技艺).
In 2013. they succeeded
A team of British and Czech scientists, led by Dr Tomas Cizmar. say
they have created a rea-life "tractor beam". like the kind from Star Trek . which uses a line of
light to attract objects. at least at a microscopic level
Light control techniques have existed since the l970s. but this is thought to be the first
time a beam has been used to draw objects towards a light source
Usually when microscopic
objects are hit by a line of light. they are forced along the direction of the beam
After many
years' research. Dr Cizmar's team discovered a technique that allows for the radiant force(辐射力) of light to be changed and to use the negative force to draw out certain particles(小颗粒)
Dr Cizmar says that even though it is a few years away from practical use. the technology has huge potential for medical research
In particular. the tractor beam is highly selective in the particles it can attract. so it can pick up particles that have specific characteristics. such as size or composition. in a mixture
"Eventually, this could be used to separate white blood cells. for example," Dr Cizmar told BBC News
It has been a primary plot design in science fiction TV programs and movies to allow ob-
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