第二篇
Superconductor Ceramic(陶瓷)
An underground revolution begins this winter．with the flip(轻击)of a switch，30，000
homes in one part of Detroit will soon become the first in the country to receive electricity
transmitted by ice．cold high．performance cables．Other American cities are expected to follow
Detroit’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 because
they are made of superconductors．A superconductor is a material that transmits electricity with
little or no resistance．Resistance is the degree to which a substance resists electric current．All
common electrical conductors have a certain amount of electrical resistance．They convert at
least 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 10se its resistance．The first superconductors，made more than 50
years ago，had to be cooled to一263 degrees Celsius before they lost their resistance．Newer
superconducting materials 10se their resistance at一143 degrees Celsius．
The superconductors cable installed at the Frisbie station is made of a ceramic material
that contains copper．oxygen．bismuth(铋)。strontium(锶)．and calcium(钙)．A ceramic is a
hard．strong compound made from clay or minerals．The superconducting ceramic has been
fashioned into a tape that is wrapped lengthwise around a long tube filled with liquid nitrogen．
Liquid nitrogen is supercold and lowers the temperature of the ceramic tape to the point where it
conveys electricity with zero resistance．
The United States loses an enormous amount of electricity each year to resistance．
Because cooled superconductors have no resistance．they waste much less power．0ther cities
are watching the Frisbie experiment in the hope that they might switch to superconducting cable
and conserve power．too．
36 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一263 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．
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