Read and translate the text. 1. Practice the following words

Nanomaterials

Unit IV

1. Practice the following words:

Ratio ['rei∫iəu], ion ['aiən], opaque [əu'peikou], combustible [kəm'bΛstibl], catalyst ['kætlist], inert [i'nз:t].

2. Study the vocabulary list:

Reduction - сокращение

quantum effects – квантовые эффекты

ratio – отношение

catalytic – каталитический

ion – ион

opaque – непрозрачный

transparent – прозрачный

insoluble – нерастворимый

inert – инертный

catalyst - катализатор

Larger to smaller: a materials perspective

A number of physical phenomena become pronounced as the size of the system decreases. These include statistical mechanical effects, as well as quantum mechanical effects, for example the “quantum size effect” where the electronic properties of solids are altered with great reductions in particle size. This effect does not come into play by going from macro to micro dimensions. However, quantum effects become dominant when the nanometer size range is reached, typically at distances of 100 nanometers or less, the so called quantum realm. Additionally, a number of physical (mechanical, electrical, optical, etc.) properties change when compared to macroscopic systems. One example is the increase in surface area to volume ratio altering mechanical, thermal and catalytic properties of materials. Diffusion and reactions at nanoscale, nanostructures materials and nanodevices with fast ion transport are generally referred to nanoionics. Mechanical properties of nanosystems are of interest in the nanomechanics research. The catalytic activity of nanomaterials also opens potential risks in their interaction with biomaterial. Materials reduced to the nanoscale can show different properties compared to what they exhibit on a macroscale, enabling unique applications. For instance, opaque substances become transparent (copper); stable materials turn combustible (aluminum); insoluble materials become soluble (gold). A material such as gold, which is chemically inert at normal scales, can serve as a potent chemical catalyst at nanoscales. Much of the fascination with nanotechnology stems from these quantum and surface phenomena that matter exhibits at the nanoscale.

4. Find in the text English word-combinations corresponding to the following Russian ones:

Сокращение размера частиц;изменять электронные свойства твердых частиц; изменять физические свойства материалов; исследования в наномеханике; механические свойства наносистем; взаимодействие наноматериалов с биоматериалами; уменьшать материалы до наноуровня; превращать непрозрачные вещества в прозрачные; быть инертным; служить мощным химическим катализатором на наноуровне.

5. Complete the following sentences:

1) Quantum effects become dominant when the nanometer size range is reached, typically at distances of ….

2) Diffusion and reactions at nanoscale, nanostructures materials and nanodevices with fast ion transport are generally referred to ….

3) Mechanical properties of nanosystems are of interest in ….

4) Opaque substances reduced to the nanoscale become ….

5) Stable materials reduced to the nanoscale turn ….

6) Insoluble materials reduced to the nanoscale become ….

7) Gold, which is chemically inert at normal scales, can serve as ….

6. Answer the following questions:

1) Why do statistical mechanical effects and quantum mechanical effects become pronounced?

2) When do quantum effects become dominant?

3) What does nanomechanics study?

4) Do materials reduced to the nanoscale exhibit the same properties as on a macroscale?

5) When can gold serve as a potent chemical catalyst?