"Harry Hill Road, how to fly to heaven"?

Superconductor phenomenon makes "Harry road, DJ."

In the lab showed "Meissner effect".

Information picture Beijing News weekly of the new knowledge

The film ' where da "have a floating in the air" Harry road ORI ".

Recently, Zhangjiajie scenic health and life of this Office is to drag down the mountain. So in fact, quite a letdown. You know, Harry road, Morro of suspension, it is let out human figures, who eradicated Neville. All this and superconductivity.

Because of the "resistance", so the charge after wire is some energy left, transformed into heat.

This phenomenon is sometimes brought us considerable trouble: such as motor to generate heat, electric lines to heating, TV, laptop, refrigerators, etc., are used to generate heat, this is what we do not like. But this is just like you to take the subway, you have to buy a ticket.

However, scientists will soon have discovered a column "free subway."

In 1911, man's first observed the "superconductor" phenomenon. En-Professor in the University of Leiden in Nice, the laboratory has the world's largest and most advanced manufacturing of liquid hydrogen and liquid helium, the factory has the capacity of various metals at low temperature electrical conductivity measurement done. He found that, when the temperature down to-269 ° c around, mercury resistance. Later, he found other metals also have this phenomenon. In 1913, he was the discovery was awarded the Nobel Prize in physics.

Of course, superconducting is not only a simple zero resistance.

It also has full Diamagnetism, "Meissner effect". Superconductors "don't allow" any magnetic field inside it. If there is a magnetic field inside by superconductors, superconductors will inevitably produce a contrast of the magnetic field, ensure the internal magnetic field is zero. This forms a repulsion. When in a superconductor place a magnet just below, and the magnetic induction line vertically through superconductors, superconductors will get vertical on buoyancy. When the size of this force is equal to exactly superconductors gravity, superconductor can be suspended in the air. Human in Pandora's star on such phenomenon.

Now you know why Pandora will have so many suspended mountain.

But why are human beings like mad to get those things?

First of all, superconductors is useful.

I said before, resistance is often so boring, in order to reduce wear and tear, we think a lot of ways. Such as transmission, we have used copper resistance smaller. But copper reserves are limited and expensive, hurting, because cable is very long, so that the use of copper to create resistance, resistance is still very large. If you cannot use superconducting power transmission, there is no need to worry about resistance and fever.

Secondly, many places require huge magnetic field, the average magnet can't meet the requirements, through online circles, energized to produce.

However, the current, the stronger the more fever also, so many large magnetic fields have online circle next to continue through a large number of cold water for cooling coil. If you use superconductors, you do not need to worry about.

There is a superconducting detectors.

Superconductor developed detector near lossless, which means that the use of superconducting materials, we developed the sensitivity of the device can have a significant upgrade — the original to see 100 km radar now can see 300 km, the original not receive messages can now be received.

Although the use of superconducting materials with so many benefits, but at the current level of technology, using superconducting materials cost very expensive, and the condition is also restricted.

Superconducting materials can be limited by current strength, more than a certain limit, it becomes good conductor. This limit is called the"critical current". Many superconducting materials critical current is very small, cannot be used for transmission. Similarly, superconducting materials is also affected by the magnetic field of the "critical". The trouble is the temperature, the superconducting materials only temperature down to a very low time to change from the normal state for superconducting State.

This way, you'll understand why humans see Pandora's suspension mountain is so exciting: it was room temperature superconductors! world physicist hope a fast 100 years at room temperature superconductors, also not afraid of the weather and rain, with this in mind, just enough to let people excited.

More importantly, the big mountain, want to give him holding up, what great force required, only a very strong magnetic field. This means that their critical magnetic field also huge — temperature, corrosion resistance, super strong magnetic field of the critical, it is the perfect superconductors. It is like a film described as supporting the further development of human civilization.

□ Xiaoyuanshan (Shanghai physics doctoral)