第 40 至 43題為題組
In science fiction TV programs such as Star Trek, tractor beams are used to tow spaceships and
move objects. For years, scientists have labored to replicate this feat. In 2013, they succeeded. A team of
British and Czech scientists, led by Dr. Tomas Cizmar, say they have created a real-life “tractor beam,”
like the kind from Star Trek, which uses a beam of light to attract objects, at least at a microscopic level.
Light manipulation techniques have existed since the 1970s, but this is thought to be the first time a
light beam has been used to draw objects towards a light source. Usually when microscopic objects are hit
by a beam 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 of light to be reversed and to use
the negative force to draw out certain particles.
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 properties, 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 device in science fiction TV programs and movies to allow objects like
spaceships to be trapped in a beam of light. But Dr. Cizmar said this particular technique would not
eventually lead to that. A transfer of energy happens in the process. On a microscopic scale that is OK,
but on a large scale it would cause huge problems. A large object could be destroyed by the heating,
which results from the massive amount of energy necessary to pull it.
【題組】41. Which of the following is true about Dr. Cizmar’s tractor beam?
(A) It moves big objects as the tractor beam did in Star Trek.
(B) It is the first light beam device that pushes objects forward.
(C) It relies on negative force to pull out specific kinds of particles.
(D) It is currently being used for separating blood cells in medical research.
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