Гвоздева Пхысицс фор адванцед студентс 2011
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III. Make the sentences sound less categorical using S + seem (appear) + to V; S + do (does) not seem (appear) + to V
1.Neither the initial conditions, nor the values of the parameters in the theory are arbitrary.
2.Both the initial conditions and the values of the parameters are somehow chosen very carefully.
3.There is a very large number of different, separate universes with different values of the physical parameters and different initial conditions.
4.Most of these universes do not provide the right conditions for the development of the complicated structures needed for intelligent life.
CLASS EXERCISES
Exercise 1 (in groups)
Sharing ideas
Follow the passage.
1.Why do stable nuclides exist?
2.Why do elements exist?
3.Where are nuclides built up?
4.Why do stars exist?
5.How were stars formed?
6.Why does the universe exist?
7.What does one of the versions of the anthropic principle state?
8.What makes the existence of intelligent human species on the earth possible?
Exercise 2 (do it yourself)
Translate the sentences, then compare your translation with the original sentences and make corrections, if any.
1.Теоретически ни начальные условия, ни значения параметров не являются произвольными.
2.Согласно принципу энтропии существует множество вселенных с различными значениями физических параметров и различными начальными условиями.
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3.На большинстве этих вселенных не созданы те условия, которые нужны для развития сложных, разумных структур.
4.Для развития разумной жизни нужны условия и параметры, соответствующие нашей вселенной.
A NUMBER PROVIDED BY NATURE
Run through the passage and say what Paul Dirac thinks about dimensionless numbers.
“The large numbers hypothesis concerns dimensionless numbers provided by nature. An example of a dimensionless number is the ratio of the mass of the proton to the mass of the electron. There is another dimensionless number which connects Planck’s constant and the electronic charge. This number is 137, quite independent of the units. When a dimensionless number like that turns up, a physicist thinks there must be some reason for it. At present one cannot set it up.
There is another dimensionless number which is of importance. If you have an electron or a proton, the electric force between them is inversely proportional to the square of the distance; the gravitational force is also inversely proportional to the square of the distance. The ratio of those two forces does not depend on the distance. The ratio gives you a dimensionless number. That number is extremely large, about ten to the power thirty-nine. It’s a number provided by nature and we should expect that a theory will some day provide a reason for it.”
Paul Dirac
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Part IV. NUCLEAR ENGINEERING
UNIT 1
LASERS
Lasers show up in an amazing range of products and technologies. You will find them in everything from CD players to dental drills, from high-speed metal cutting machines to measuring systems. They all use lasers. But what is a laser? And what makes a laser beam different from that of a flashlight?
PRE-READING TASK
Give Russian correspondence:
once (as soon as, when), eventually (finally), to control (to regulate), the way (how), although (though), in general (ant. in particular), versus (against, as opposed to), after, in the form, specific (certain, particular), in contrast (visi versa), operation (work), in terms of (in view of), N + that
ABSORBTION OF ENERGY
Study the text. Mind the underlined grammar points.
An atom absorbs energy in the form of heat, light, or electricity. Once an electron moves to a higher energy orbit, it eventually wants to return to the ground state. When it does, it releases its energy as a photon – a particle of light. You can see atoms releasing energy as photons. For example, the heating element in a toaster turns bright red because atoms, excited by heat, release red photons. A picture on a TV screen is made up by phosphor atoms emitting light of different colors. Flashlights, fluorescent lights and, incandescent bulbs produce light because electrons change their orbit and release photons.
THE LASER
A laser is a device that controls the way energized atoms release photons. “Laser” is an acronym for light amplification by stimulated emission of radiation. Although there are many types of lasers, all of them
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have some common essential features. In a laser, the lasing medium is pumped to excite the atoms. For the laser to work efficiently it is necessary to have a large collection of atoms in the excited state. In general, the atoms are excited to a level that is two or three levels above the ground state. This increases the degree of population inversion. The population inversion is the number of atoms in the excited state versus that in the ground state.
After the electron absorbed the amount of energy necessary to reach the excited level, it releases this energy. The emitted energy comes out in the form of photons. The emitted photon has a specific wavelength (color) that depends on the energy state of the electron when the photon is released. Two identical atoms with electrons in identical states will release photons with identical wavelengths.
PROPERTIES OF LASER LIGHT
Laser light is different from normal light. Laser light has the following properties:
1.It is monochromatic. It contains one specific wavelength of light (one specific color). The wavelength of light is determined by the amount of energy released when the electron drops to a lower orbit.
2.It is coherent. It is ‘organized’ – each photon moves in step with the others. This means that the wave fronts of all the photons launch in unison.
3.It is directional. Laser light has a very tight, intense and concentrated beam, because photon emission is stimulated. In contrast, a flashlight releases photons randomly, which makes its beam weak and diffuse.
The wavelength of the photon depends on the energy difference between the excited state and the ground state. Stimulated emission occurs when a photon encounters another atom with the electron in the same excited state. The first photon would stimulate or induce atomic emission in such a way that the photon emitted from the second atom vibrates with the same frequency and direction as the incoming photon.
The other key to a laser operation is a pair of mirrors, one at each end of the lasing medium. Photons reflect off the mirrors to travel back and forth through the lasing medium. In the process, they would stimulate other electrons to energy transition and would cause the emission of
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more photons of the same wavelength and phase. The mirror at the end of a laser is half-silvered, meaning it reflects some light and lets some light through. The light that it lets through is the laser light.
Vocabulary Notes
1.an incandescent bulb is made of glass and gives out light when electricity passes through it.
2.to amplify – to increase intensity
3.to stimulate – (here) to excite – to induce – to cause the emission of photons
4.identical – similar – things that are identical are exactly the same
5.to encounter – to meet with
6.the frequency of a light wave is the rate with which it vibrates.
POST-READING TASK
(To be done at home in writing) I. Speak about.
1.a photon
2.a picture on a TV screen
3.an incandescent bulb
4.the population inversion.
5.colors
6.The wavelength of a photon
7.the common features all lasers have
II. What does it mean?
1.The laser light is monochromatic.
2.The laser light is coherent.
3.The laser light is directional.
III. Formulate questions.
1.The wavelength of the photon depends on …….. (What?)
2.Stimulated emission occurs …………………...... (When?)
3.The first photon would stimulate atomic emission in such a way ……. (In what way?)
4.The two mirrors are placed …………….. (Where?)
5.The mirror at the end of a laser is half-silvered. (Why?)
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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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