单项选择题

变压器的铁损又称为空载损耗,其大小与铁芯材质有关,与负荷电流( )。

A.成正比
B.成反比
C.无关
D.平方成正比
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Stanford University1.Stanford University, famous as one of northern California's several institutions higher learning, is sometimes called 'the Harvard of the West'.The closeness of Stanford to San Francisco, a city thirty-two miles to the north, gives the university a decidedly cosmopolitan (世界性的) flavor.2.The students are enrolled mainly from the western United States. But most of the fifty states send students to Stanford, and many foreign students study here as well..And standards for admission remain high.Young men and women are selected to enter the university from the upper fifteen percent of their high school classes.3.Not only because of the high caliber (素质,才干) of its students but also because of the desirable location and climate, Stanford has attracted to its faculty some of the world's most respected scholars.The university staff has included many Nobel Prize winners such as Dr.Felix Bloch,Dr.Robert Hofstadter, and Dr.William Shockley in physics, Dr.Author Kornberg and Dr. Joshua Lederberg in medicine, and Dr.Paul J.Flory and Dr.Linus Pauling in chemistry.The Russian novelist Aleksandr Solzhenistsyn has been in residencE.Stanford's undergraduate school of engineering and its graduate schools of business, law, and medicine are especially well-regardeD.4.What is student life like on 'the Farm'? Culturally, the campus is a magnet for both students and citizens of nearby communities.Plays, concerts, and operas are performed, in the university's several .auditoriums and in its outdoor theater, where graduations are also helD.Several film series are presented during the school year.Guest lecturers from public and academic life frequently appear on campus: In the evenings, many students gather to socialize in the Student Union's coffee house; here the beverages (饮料) and the atmosphere both have a decidedly European flavor.For the sports-minded, the Sranford campus offers highly developed athletic facilities.Team sports, swimming, and track and field activity are all very much part of the Stanford picturE.So are bicycling and jogging.5.In addition to financial support from alumni (校友), Stanford receives grants from the government and from private philanthropic (慈善的) foundations.In recent years, government grants have made possible advanced studies in the fields of history, psychology, education, and atomic energy.At present Stanford is carrying out an ambitious building program, financed in part by the Ford Foundation's 25 million grant.Recently added to the campus are a new physics building, new school of business, new graduate school of law, new student union, and undergraduate library.第 23 题 Paragraph 2_________A.Colorful life on the campusB.Intelligent student bodyC.School administrationD.Distinguished facultyE.Substantial financial supportF.The Harvard of the West
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Development and the Protection of EnvironmentModern technology has developed in a manner which often conflicts with the environment. The many industrial pollutants constantly impact the environment in a harmful way. Nevertheless, it is possible and practical to achieve a high level of technology, with- out altering the overall natural environment.There are two basic methods of conserving the natural environment. One is alternative technology in which techniques (such as windmills and solar energy) must be found for providing power. The other is to try to minimize the, effects of modern technology by the more efficient: use of materials and more, effective pollution control.There comes a point when the quality of life can no longer be, improved because of the high population density and the largely unsuccessful attempts to meet its demands.Present energy policies of the western world are considering new energy sources to meet the demands of a growing population. The main Sources used have been oil, gas, and coal-which are in limited supply-- and nuclear power, which has problems concerning radioactive waste storagE.Wind and solar energy are alternative possibilities, but only solar energy is likely to become a main power source for many countries.Many of the materials used daily in a technological society are destined to be discarded, Rags, paper, metal, glass, and plastics are all substances that could be recycled or reuseD.Research is being done to determine methods of separating useful products from industrial and domestic wastE.The processing of sewage is also helpful. This is collected in gasholders and burned to produce heat and create electricity. The waste itself is often used for soil enrichment.第 41 题 Modern technology is harmful to the natural environment mainly becauseA.of industrial pollutantsB.it has become too expensiveC.it has become too complicatedD.it consumes all natural resources
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