题干

科学家最新开发的一种新原理二次电池的能量密度是现行锂电池的7倍,该电池结构如图所示,下列有关说法正确的是(   )

A:电池放电时Li+向负极移动

B:电池放电时,正极的电极反应式为:2Li++Li2O2+2e﹣═2Li2O

C:电池充电时,Li极应与外电源的正极相连

D:电池系统内进入二氧化碳及水对电池性能不会产生影响

上一题 下一题 0.0难度 选择题 更新时间:2010-05-06 09:08:44

答案(点此获取答案解析)

B

同类题3

阅读理解

    On the morning of May 20, 1927, Charles A. Lindbergh Jr. took off from a muddy airfield in New York and headed for Paris. During the first fourteen hours of flying, he had had some anxious moments. Sleet had gathered on the wings of the plane and the fog was so thick that he could hardly see the tips of the wings. However, he had come across equally dangerous flying conditions before. Of course, now that he was over the ocean, his parachute(降落伞)was useless. He had only one choice: he had to go on.

    Although he had waited a long time to make this trip, he did not feel strange or nervous. He was accustomed to flying alone, and he had flown this route in his imagination many times. The idea of flying across the Atlantic had occurred to him one night when he had been carrying the mail between St. Louis and Chicago. That night, he told himself that a solo non-stop flight between New York and Paris was possible. He knew that airplanes capable of making the long flight over the ocean could be built. A man of skill and endurance could make his dream come true.

    As he was recalling that night, he reduced the altitude of the plane. Close to the surface of the ocean, he found that the ice on the wings began to melt and the fog disappeared. For the time being, at least, he was safe. The steady sound of the motor seemed like music in his ears. He had perfect confidence in his plane because he knew that there was not a more dependable plane than his. The Ryan Aircraft Company had constructed the plane to meet his special needs. He had worked with the chief engineer of the company, Donald Hall, to produce the airplane as rapidly as possible. Although Hall had worked with the basic design of the Ryan airplane, he had had to make many modifications. As a result, it was a very special airplane. He had named it “The Spirit of St. Louis,” in honour of the St. Louis businessmen whose financial backing had made the trip possible. Besides their money, he had invested all of his own savings, which came to two thousand dollars, in the venture.

    At 12:10 on the afternoon of May 21, Lindbergh caught sight of the coast of Ireland. Now that the flight was almost over, he began to relax a little. Finally, after thirty-four hours in the air without sleep, he arrived at Le Bourget Field, in Paris.