2014-02-17
911
Molecular nanotechnology
Unit VI
1. Practice the following words:
Monoxide [mə'na:ksaid], hybrid ['haibrid], silicon ['silikən], oscillator ['a:sileitə].
2. Study the vocabulary list:
Molecular nanotechnology – молекулярная нанотехнология
monoxide – одноокись
oscillator – генератор
premise – предпосылка
voltage – напряжение
Molecular nanotechnology: a long-term view
Molecular nanotechnology, sometimes called molecular manufacturing, describes engineered nanosystems (nanoscale machines) operating on the molecular scale. Molecular nanotechnology is especially associated with the molecular assembler, a machine that can produce a desired structure or device atom-by-atom using the principles of mechanosynthesis. Manufacturing in the context of productive nanosystems is not related to, and should be clearly distinguished from, the conventional technologies used to manufacture nanomaterials such as carbon nanotubes and nanoparticles. When the term "nanotechnology" was independently coined and popularized by Eric Drexler (who at the time was unaware of an earlier usage by Norio Taniguchi) it referred to a future manufacturing technology based on molecular machine systems. The premise was that molecular scale biological analogies of traditional machine components demonstrated molecular machines were possible: by the countless examples found in biology, it is known that sophisticated, stochastically optimised biological machines can be produced.
It is hoped that developments in nanotechnology will make possible their construction by some other means, perhaps using biomimetic principles. However, Drexler and other researchers have proposed that advanced nanotechnology, although perhaps initially implemented by biomimetic means, ultimately could be based on mechanical engineering principles, namely, a manufacturing technology based on the mechanical functionality of these components (such as gears, bearings, motors, and structural members) that would enable programmable, positional assembly to atomic specification. The physics and engineering performance of exemplar designs were analyzed in Drexler's book Nanosystems. In general it is very difficult to assemble devices on the atomic scale, as all one has to position atoms on other atoms of comparable size and stickiness. Another view, put forth by Carlo Montemagno, is that future nanosystems will be hybrids of silicon technology and biological molecular machines. Yet another view, put forward by the late Richard Smalley, is that mechanosynthesis is impossible due to the difficulties in mechanically manipulating individual molecules. This led to an exchange of letters in the ACS publication Chemical & Engineering News in 2003.Though biology clearly demonstrates that molecular machine systems are possible, non-biological molecular machines are today only in their infancy. Leaders in research on non-biological molecular machines are Dr. Alex Zettl and his colleagues at Lawrence Berkeley Laboratories and UC Berkeley. They have constructed at least three distinct molecular devices whose motion is controlled from the desktop with changing voltage: a nanotube nanomotor, a molecular actuator, and a nanoelectromechanical relaxation oscillator. An experiment indicating that positional molecular assembly is possible was performed by Ho and Lee at Cornell University in 1999. They used a scanning tunneling microscope to move an individual carbon monoxide molecule (CO) to an individual iron atom (Fe) sitting on a flat silver crystal, and chemically bound the CO to the Fe by applying a voltage.
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4. Find in the text English words and word-combinations corresponding to the following Russian ones:
Углеродные нанотрубки; наночастицы; производить наноматериалы; действовать на молекулярном уровне; основываться на механических инженерных принципах; управлять движением молекул; молекулярная нанотехнология; разработки в нанотехнологии.
5. Say whether the following statements are true or false:
1) Molecular nanotechnology and molecular manufacturing mean the same.
2)Molecular assembler is a machine, that produce desired structure or device atom-by-atom using the principles of mechanosynthesis.
3)Molecular manufacturing is related to technologies used to manufacture nanomaterials such as carbon nanotubes and nanoparticles.
4)It is not an easy matter to assemble devices on the atomic scale, as all one has to position atoms on other atoms of comparable size and stickiness.
5)The possibility of molecular machine systems is undoubted.
6)Non-biological molecular machines are in wide usage today.
6. Answer the following questions:
1) What does molecular nanotechnology describe?
2) What is molecular assembler?
3) Why is it difficult to assemble devices on the atomic scale?
4) What did leaders in research on non-biological molecular machines construct?
5) What did researchers from Cornell University use to indicate that positional molecular assembly is possible?
