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Superconductors in Action

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Superconductors in Action

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    1. Superconductors in Action Last week I discussed what superconductivity was. For those who weren’t here supercontivitiy is a state of matter where…. This week I’ll discuss some applications. Describe a few pictures.Last week I discussed what superconductivity was. For those who weren’t here supercontivitiy is a state of matter where…. This week I’ll discuss some applications. Describe a few pictures.

    2. Superconductors: Properties and Uses Include outline of the present talk in this slide * How we cool matter. * Two types of applications: Those that involve the ability of s.c’s to carry dissipationless, or near dissipationless current as low frequencies. * Those that involve the quantum nature of the cooper pairs, all in the same state, behaving as a single quantum mechanical particle. Demos: 1. Rope and tennis ball. 2. microwave tunneling 3. something about the principles of bandwidth in r.f. for communications? 5. fineness of atomic spectral lines with prism or diffraction grating. 6. jumping ring in a solenoid (perhaps). 7. electromagnet again (perhaps). 8. demonstrate some principle behind refrigeration (compressor, pumping)? 9. CO2 cartridge Include outline of the present talk in this slide * How we cool matter. * Two types of applications: Those that involve the ability of s.c’s to carry dissipationless, or near dissipationless current as low frequencies. * Those that involve the quantum nature of the cooper pairs, all in the same state, behaving as a single quantum mechanical particle. Demos: 1. Rope and tennis ball. 2. microwave tunneling 3. something about the principles of bandwidth in r.f. for communications? 5. fineness of atomic spectral lines with prism or diffraction grating. 6. jumping ring in a solenoid (perhaps). 7. electromagnet again (perhaps). 8. demonstrate some principle behind refrigeration (compressor, pumping)? 9. CO2 cartridge

    3. Low Temperatures As I mentioned some materials turn into superconductors, but only at low temperature. What is low temperature? Kelin scale.As I mentioned some materials turn into superconductors, but only at low temperature. What is low temperature? Kelin scale.

    5. How do we cool: compress gas until it becomes liquid: When you compress a gas to a liquid gets hot. demonstration: plunger I’m not strong enough to compress air to a liquid Allow the high pressure liquid to cool to room temperature at high pressure. demonstration CO2. As the liquid evaporates and explands it cools. Compressor and temperature. Vapor compression systems are employed in most refrigeration systems. Here, cooling is accomplished by evaporation of a liquid refrigerant under reduced pressure and temperature. The fluid enters the compressors at state 1 where the temperature is elevated by mechanical compression (state 2). The vapor condenses at this pressure, and the resultant heat is dissipated to the surrounding. The high pressure liquid (state 3) then passes through an expansion valve through which the fluid pressure is lowered. The low-pressure fluid enters the evaporator at state 4 where it evaporates by absorbing heat from the refrigerated space, and reenters the compressor. The whole cycle is repeated. How do we cool: compress gas until it becomes liquid: When you compress a gas to a liquid gets hot. demonstration: plunger I’m not strong enough to compress air to a liquid Allow the high pressure liquid to cool to room temperature at high pressure. demonstration CO2. As the liquid evaporates and explands it cools. Compressor and temperature. Vapor compression systems are employed in most refrigeration systems. Here, cooling is accomplished by evaporation of a liquid refrigerant under reduced pressure and temperature. The fluid enters the compressors at state 1 where the temperature is elevated by mechanical compression (state 2). The vapor condenses at this pressure, and the resultant heat is dissipated to the surrounding. The high pressure liquid (state 3) then passes through an expansion valve through which the fluid pressure is lowered. The low-pressure fluid enters the evaporator at state 4 where it evaporates by absorbing heat from the refrigerated space, and reenters the compressor. The whole cycle is repeated.

    6. Boiling Points of Liquids

    7. Applications of Superconductors

    8. High Currents in Tight Places     Demo, Electromagnet    Demo, Electromagnet

    9. Filters in Cell Phone Towers Demo FM:Demo FM:

    11. Quantum Devices

    13. Tunneling: The strange world of quantum mechanics

    18. ….. What this means in practice, is that if you send in a bunch of particles…….. What this means in practice, is that if you send in a bunch of particles…

    20. An Example: Microwave Tunneling

    22. The Josephson Effect: aka Cooper Pair Tunneling (1962 predicted, 1973 Nobel Prize)

    25. The a.c. Josephson Effect

    34. I tried to set up a demonstration of this…just kidding No volation of energy conservation. Fundamental constants of natureI tried to set up a demonstration of this…just kidding No volation of energy conservation. Fundamental constants of nature

    35. We have a device …. I studied the josephson effect in graduate school.We have a device …. I studied the josephson effect in graduate school.

    37. DEMO: dim lightsDEMO: dim lights

    39. Related through fundamental constants of nature… Finally the most sensitive detectors of magnetic fields are….Related through fundamental constants of nature… Finally the most sensitive detectors of magnetic fields are….

    40.

    41. Squids depend on the magnetic field properties of supercondcutors…Squids depend on the magnetic field properties of supercondcutors…

    42. I mentioned last week that a superconductor will expel all magnetic fieldsI mentioned last week that a superconductor will expel all magnetic fields

    43. Demonstrations:Demonstrations:

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