Добавил:
Upload Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз: Предмет: Файл:
exam 03.05.doc
Скачиваний:
0
Добавлен:
01.07.2025
Размер:
179.71 Кб
Скачать

Task one. Get ready to translate first four passages and to give a summary of the text. Thinnest silicon-chip wires refuse to go quantum

06 January 2012 by Anil Ananthaswamy

Not everything is weird at the nanoscale. Wires so small you'd expect them to obey the strange laws of quantum mechanics have instead displayed the same electrical properties as ordinary electrical interconnects.

The finding bodes well for conventional computers, because these tiny, conductive wires could make chips smaller. It could be bad news, though, for the super-fast quantum computers that are hoped to come next.

So far, conventional computers have followed Moore's law: the density of transistors that a conventional integrated-circuit chip can hold doubles approximately every two years, yielding ever-better performance out of ever-smaller devices.

However, it's getting harder to build smaller interconnects to wire up the devices on the silicon chip. As the width of metal wires drops to few tens of nanometres, their resistivity soars because electrons start interacting with nearby surfaces, dissipating more heat and lowering efficiency.

Also, as wires get down to nanometre scales, quantum behaviour usually dominates. For instance, the entire wire can exist in a superposition of states because of a property called quantum coherence. The wave behaviour of electrons in the wire might then cause them to interfere with each other, disrupting the electrical properties you would expect to see at larger scales.

Now it is proved by the experiments that a silicon chip just 1.5 nanometres wide behaves just like larger wires. The trick was to infuse them with phosphorus atoms, which provide electrons that can move freely and conduct electricity, turning each channel into a wire. Because the entire wire, except for its ends, was enclosed in the silicon, it was isolated from other surfaces that could disrupt its conductivity.

The team found that these wires conducted electricity nearly as well as state-of-the-art copper interconnects used in modern microprocessors – despite being much thinner. Moreover, when they built wires of different lengths, the wires followed Ohm's law, in which the resistance of a wire increases with length – a property of non-quantum, or "classical" conductors.

TASK TWO. Discuss the given abstract.

Olympus has released the new CX22LED and CX22HAL microscopes for routine and educational microscopy. The CX22 series features quick and convenient microscopy with an expanded field of view and increased comfort. The easy setting of different viewing heights is ideal for use in an educational setting where users are changing frequently. The CX22LED clinical microscope with built-in light emitting diode (LED) illumination offers consistent long-term performance for biological and medical applications. This cost-effective imaging system can illuminate samples with a similar light intensity to that provided by halogen bulbs. Furthermore, the LED light source produces a more uniform, controllable and stable illumination for high-quality imaging. As an environmentally-friendly and easy-to-use system, this microscope is also ideal for educational use.

Соседние файлы в предмете [НЕСОРТИРОВАННОЕ]