Text b Mechanical Properties of Nanotubes

Elastic Properties:

These nanotubes are the strongest fibers known. A single perfect nanotube is about 10 to 100 times stronger than steel per unit weight.

The maximum tensile strength is being about 100 GPa. If the tube is considered to be a solid cylinder, then it would have a lower Young's modulus. If the tube is considered to be hollow, the modulus gets higher, and the thinner we treat the walls of the nanotube, the higher the modulus will become.

Nanotubes as Nanobalances:

Since nanotubes can be resonated, they can be used as tools to measure physical properties. Resonance methods are very sensitive and accurate. Anything that will shift or dampen the resonance can then be accurately measured. To give an important application, a mass attached to the end of a nanotube will reduce the resonance frequency allowing us mass calculations.

Nanotube weighing a carbon sphere :

Nanobalance application for the nanotubes: a mass attached at the end of the nanotube shifts its resonance frequency. If the nanotube is calibrated (i.e. its spring constant known), it is possible to measure the mass of the attached particle. The resonant frequency was 968 kHz, compared to 3.28 MHz when unloaded (calculated). The mass of this carbon sphere was then determined to be 22±6 fg. Direct estimate based on volume and amorphous graphite density gives a mass close to 30 fg.

I.New words:

property - якість hollow – порожній, пустий

weight – вага frequency – частота

tensile strength – міцність при розтягуванні volume – об’єм, маса

modulus [´modjules] – модуль, коефіцієнт density – густота

the thinner ... the higher ... – чим тонкіше...тим вище...

Exercises. Grammar: The Gerund

II.Give the initial forms of the given words

Strongest, lower, higher, gets, will become, measured, allowing, us.

III.Translate the following sentences and define the gerund in them

1.Most people like speaking foreign languages.

2.The problems of protecting enviroment concern all the people in the world.

3.I know of his having been sent to work to the Far East.

4.Reading English technical magazines is important for an engineer.

5.Upon making a number of experiments atomic physicists solved the problem of building a very powerful miscroscope.

IV.Put as many questions to the following sentence as possible

Studies of the gate-voltage dependence of tunneling resonance widths have shown that nonequilibrium excitations in the nanoparticle are a primary source of resonance broadening.

Give an annotation of Text B in English