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Most old men consider themselves to be______________
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The bhavior sensor and software system bilt in a phone
A．mentally B．artificially C．manually D．automatically
A．financial B．original C．social D．historical
Superconducting Ceramic (陶瓷)
An underground revolution begins thiswinter. With the flip (轻击) of a switch,30,000homes in one part of Detroitwill soon become the first in the country to receive electricity transmitted byice-cold high-performance cables. Other American cities are expected to follow Detroit's example in theyears ahead, which could conserve enormous amounts of power.
The new electrical cables at the Frisbiepower station in Detroitare revolutionary because they are made of superconductors. A superconductor isa material that transmits electricity with little or no resistance. Resistanceis the degree to which a substance resists electric current. All commonelectrical conductors have a certain amount of electrical resistance. Theyconvert 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. Asuperconducting material has to be cooled to an extremely low temperature tolose its resistance. The first superconductors, made more than 50 years ago,had to be cooled to -263 degrees Celsius before they lost their resistance.Newer superconducting materials lose their resistance at -143 degrees Celsius.
The superconductors cable installed at theFrisbie station is made of a ceramic materialthat contains copper, oxygen, bismuth (铋), strontium (锶), andcalcium (钙). A ceramic is a hard, strong compound madefrom clay or minerals. The superconducting ceramic has been fashioned into atape that is wrapped lengthwise around a long tube filled with liquid nitrogen.Liquid nitrogen is supercold and lowers the temperature of the ceramic tape tothe point where it conveys electricity with zero resistance.
The United States loses an enormousamount of electricity each year to resistance.Because cooled superconductorshave no resistance, they waste much less power.Other cities are watching theFrisbie experiment in the hope that they might switch to superconducting cableand conserve power, too.
第 31 题 What is the benefit of the revolutionmentioned in the first paragraph？
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