Superconductor Ceramic (陶瓷)

An underground revolution begins this winter. With the flip (輕擊) of a switch,30,000homes in one part of Detroit will soon become the first in the country to receive electricitytransmitted by ice cold high performance cables. Other American cities are expected to followDetroit's example in the years ahead, which could conserve enormous amounts of power.

The new electrical cables at the Frisbie power station in Detroit are revolutionary becausethey are made of superconductors. A superconductor is a material that transmits electricity withlittle or no resistance. Resistance is the degree to which a substance resists electric current. Allcommon electrical conductors have a certain amount of electrical resistance. They convert atleast some of the electrical energy passing through them into waste heat. Superconductors don't.No one understands how superconductivity works. It just does.

Making superconductors isn't easy. A superconductor material has to be cooled to an extremely low temperature to lose its resistance. The first superconductors, made more than 50years ago, had to be cooled to -263 degrees Celsius before they lost their resistance. Newersuperconducting materials lose their resistance at -143 degrees Celsius.

The superconductors cable installed at the Frisbie station is made of a ceramic material thatcontains copper, oxygen, bismuth (鉍), strontium (鍶), and calcium (鈣). A ceramic is ahard, strong compound made from clay or minerals. The superconducting ceramic has beenfashioned into a tape that is wrapped lengthwise around a long tube filled with liquid nitrogen.Liquid nitrogen is super cold and lowers the temperature of the ceramic tape to the point where itconveys electricity with zero resistance.

The United States loses an enormous amount of electricity each year to resistance. Becausecooled supercondUutors have no resistance, they waste much less power, other cities arewatching the Frisbie experiment in the hope that they might switch to superconducting cable andconserve power, too.

What is the benefit of the revolution mentioned in the first paragraph?

A.With a flip of swish, electricity can be transmitted.

B.Other American cities can benefit from the high-performance cables.

C.Great amounts of power can be conserved.

D.Detroit will first receive electricity transmitted by the new electrical cables

37、 Compared to common electrical conductors, superconductors__________

A.have little or no electrical resistance

B.Can be used for along time

C.are not energy-efficient

D.can be made easily

38、 At what temperature does the superconducting ceramic lose its resistance__________?

A.-143 degree Celsius.

B.-263 degree Celsius.

C.As long as it is ice-cold.

D.Absolute zero.

39、 What element enables the ceramic tape to lower its temperature__________?

A.Copper.

B.Liquid nitrogen.

C.Clay.

D.Calcium.

40、 According to the last paragraph, which of the following statements is NOT true__________?

A.Other cities hope they Can also conserve power.

B.Other cities hope they Can use superconducting cables soon.

C.Superconductors waste less power because of their low resistance.

D.The Fribie experiment is not successful.

（責任編輯：vstara）

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