CLASS EXERCISES
Exercise 1 (in pairs)
Ask and answer the questions formulated in post-reading III.
TYPES OF LASERS
FYI
a medium (s) – media (pl)
Read the text and answer the questions that follow.
There are many different types of lasers. The lasing medium can be a solid, a gas, a liquid or a semiconductor. Lasers are designated in terms of the lasing material employed.
Solid-state lasers
In solid-state lasers the lasing material is distributed in a solid matrix, such as the ruby or neodymium: yttrium-aluminum garnet “Yag” lasers. The neodymium -Yag laser emits infrared light at 1,064 nanometers (nm).
Gas lasers
Gas lasers (helium and helium-neon HeNe) are the most common gas lasers. They have an output of visible red light. CO2 lasers emit energy in the far-infrared range and are used for cutting hard materials.
Excimer lasers
Excimer is a combination of ‘excited’ and ‘dimmer’. Excimer lasers use reactive gases, such as chlorine and fluorine, mixed with inert gases such as argon, krypton or xenon. When they are electrically stimulated, a pseudo [sjud ] molecule (a dimmer) is produced. When lased, the dimmer produces light in the ultraviolet range.
Dye lasers
Dye lasers use complex organic dyes, such as rhodamine 6G, in liquid solution or suspension as lasing media. They are tunable over a broad range of wavelengths.
Semiconductor lasers
Semiconductor lasers sometimes called diode lasers are not solidstate lasers. They are electronic devices. They are very small and use
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low power. They can be built into larger arrays, such as the writing source in some laser printers or CD players.
A ruby laser
A ruby laser is a solid-state laser and emits with a wavelength of 694 nm.
Lasing medium is selected in terms of the desired emission wavelength, power needed, and pulse duration. Some lasers are very powerful, such as CO2 laser, which can cut steel. The CO2 laser is dangerous, because it emits laser light in the infrared and microwave range of the spectrum. Infrared radiation is heat, and this laser basically melts everything it is focused upon. Diode lasers are very weak and are used in pocket laser pointers. These lasers emit a red beam of light that has a wavelength between 630nm and 680 nm.
Vocabulary Notes
1.to designate – to label
2.dim – hazy – (ant. clear)
3.a dye – a substance made from plants and chemicals which is mixed into a liquid and used to change the color of something – coloring
4.an array – a matrix
5.a duration – a length of time
Answer the questions in writing.
1.What serves as the lasing medium?
2.What are the laser types?
3.What determines the selection of this or that lasing medium?
4.Into what ranges is the light spectrum divided?
5.Which laser is powerful?
6.Why is CO2 laser dangerous?
7.What wavelength of light does the diode laser have?
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UNIT 2
NANOTECHNOLOGY
MOLECULAR MANUFACTURING
PRE-READING TASK
Give Russian correspondence:
depending on, fine (very thin), an approach (a method, a technique, a way), to form, primarily (basically), compared to, although (though), at least (as a minimum), that is, largely (mainly), too + Adj., yet (but), the very, by a factor of a million, besides (in addition), specific (particular)
FYI
1.Nanotechnology is the art of manipulating materials on an atomistic or molecular scale especially to build microscopic devices.
2.The nanoscale is about a thousand times smaller than a micron. Approximately 3 to 6 atoms can fit inside of a nanometer, depending on the atom. The prefix ‘nano’ means ten to the minus ninth power of a meter, or one billionth.
3.Nanotechnologists develop and use devices that have a size of only a few nanometers. They manipulate single molecules and atoms.
ATOM-BY-ATOM ENGINEERING
Study the passage. Mind the underlined grammar points.
Manipulation of nanostructures relies on scanning probe microscopy. Using a fine tip, atoms can be manipulated for a variety of applications. This type of approach is outstanding in scientific research. For manufacturing, an array of scanning synchronized tips may be used to achieve atom-by-atom engineering. But the building rate is slow. The solution here is self-assembly. Like many biological systems, selfassembly is the most fundamental process for forming a functional and living structure.
The genetic code and the sequence built into a biosystem guide and control the self-assembling process. Self-assembly is the organization and pattern formed naturally by the fundamental building blocks such as molecules and cells. Designed and controlled self-assembly is a possible solution for future manufacturing needs.
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Nanotechnology, like any other branch of science, is primarily concerned with understanding how nature works. It will give scientists a chance to answer the questions which present day natural science can’t answer. Our efforts to produce devices and manipulate matter are at a very primitive stage compared to nature. Nature has the ability to design highly energy efficient systems that operate precisely and without waste, fix only that which needs fixing, do only that which needs doing, and no more. We do not, although one day our understanding of nanoscale phenomena may allow replicating at least a part of what nature accomplishes with ease.
Nanotechnology will give us a chance not only to manipulate matter on the nanoscale but to understand atomic scale interactions, that is, to understand the world around us.
Tim Harper (From the Nanotechnology Opportunity Report, described by NASA as the defining report in the field of nanotechnology.)
Vocabulary Notes
1.to rely on – to rest on – to be based on
2.a probe -a long thin metal instrument
3.a tip – a long fine tool used to move something delicate
4.to manufacture – to produce
5.an array – a set of, a number of
6.a rate – a speed – we use a rate speaking about processes
7.an assembly – fitting things together
8.a sequence – a series – a number of things that come one after another
9.to guide – to direct
10.to design – to create a picture of something in your mind and make a detailed drawing of it from which it can be assembled
11.to be concerned with something – to be interested in something
12.to accomplish – to achieve
POST-READING TASK
(To be done at home in writing) I. Formulate questions.
1.Manipulation of nanostructures relies on …… (What … on?)
2.Atoms can be manipulated. (How?)
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3.Atom -by-atom engineering can be achieved. (How?)
4.……. guide and control the self-assembling process. (What?)
5.Nanotechnology is primarily concerned with ……. (What with?)
6.Nanotechnology will give us a chance …………. (What chance?)
II. Translate the sentences.
1.Нанотехнология изучает мельчайшие частицы материи, кото-
рыми может манипулировать человек.
2.Нанотехнология занимается разработкой и созданием приборов и электронных схем, размеры которых не превышают несколько нанометров.
3.В нанометре могут уместиться от 3 до 6 атомов.
4.Нанотехнология может оказать воздействие на многие области науки.
5.Как и все науки, нанотехнология пытается понять, как устроен окружающий нас мир.
III. Find the topical sentence(s) in each paragraph and summarize the passage.
CLASS EXERCISES
Exercise 1 (in pairs)
Ask and answer the questions formulated in post-reading task I.
Exercise 2 (do it yourself)
Translate the sentences. Mind the underlined grammar points.
1.To continue reducing the size of semiconductors, new technologies that manipulate individual atoms will be necessary.
2.Nanotechnology is the art of manipulating materials on an atomic or molecular scale to build microscopic devices.
3.By using structure at nanoscale as a tunable physical variable, we can greatly expand the range of performance of existing chemicals and materials.
4.Understanding how electrons can be moved in a conductor by applying a potential difference led to electric lighting.
5.Fabrication and integration of nanomaterials and nanodevices may prove revolutionary for science and technology.
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