问题 多选题
如图所示,回旋加速器是加速带电粒子的装置,其核心部分是分别与高频交流电源两极相连接的两个D形金属盒,两盒间的狭缝中形成周期性变化的电场,使粒子在通过狭缝时都能得到加速,两D形金属盒处于垂直于盒底的匀强磁场中,D形盒半径为R..用该回旋加速器加速质子时,匀强磁场的磁感应强度为B,高频交流电周期为T.(粒子通过狭缝的时间忽略不计)则(  )
A.质子在D形盒中做匀速圆周运动的周期为T
B.质子被加速后的最大速度可能超过
C.质子被加速后的最大速度与加速电场的电压大小无关
D.不改变B和T,该回旋加速器也能用于加速α粒子
答案

AC

单项选择题

In War Made Easy Norman Solomon demolishes the myth of all independent American press zealously guarding sacred values of free expression. Although strictly focusing on the shameless history of media cheerleading for the principal post World War’ Ⅱ American wars, invasions, and interventions, he calls into question the entire concept of the press as some kind of institutional counterforce to government and corporate power.

Many of the examples compiled in this impeccably documented historical review will be familiar to readers who follow the news on the Internet. But such examples achieve flesh impact because of the way Solomon has organized and analyzed them. Each chapter is devoted to a single warhawk argument ( " America Is a Fair and Noble Superpower, " " Opposing the War Means Siding with the Enemy, " "Our Soldiers Are Heroes, Theirs Are Inhuman " ), illustrated with historical examples from conflicts in the Dominican Republic, E1 Salvador, Vietnam, Grenada, Panama, Kosovo, both Iraq wars, and others in which the media were almost universally enthusiastic accomplices.

The book should really be subtitled " War reporting doesn’t just suck, it kills. " It makes you feel like demanding a special war crimes tribunal for corporate media executives and owners who joined the roll-up to " shock and awe " as non-uniformed psywar ops. To be sure, this would raise the issue of whether or not following orders might suffice for the defense of obedient slaves such as Mary McGrory and Richard Cohen, who performed above and beyond the call of duty. " He persuaded me, " McGrory gushed the morning after Colin Powell addressed a plenary session of the United Nations on February 5,2003, declaring that Iraq had weapons of mass destruction. " The cumulative effect was stunning." In the same Washington Post edition, Cohen wrote.

The evidence he presented to the United Nations—some of it circumstantial, some of it absolutely bone-chilling in its detail—had to prove to anyone that Iraq not only hasn’t accounted for its weapons of mass destruction but without a doubt still retains them. Only a fool could conclude otherwise.

Solomon demonstrates how this kind of peppy prewar warm-up degenerates into drooling and heavy breathing once the killing begins. As if observing a heavy metal computer game, the pornographers of death concentrate on the exquisite craftsmanship and visual design of the murder machines, and the magnificence of the fiery explosions they produce.

It can be implied that the conflicts in E1 Salvador, Vietnam, Grenada, Panama, Kosovo()

A. created heroes

B. are forgotten by most Americans

C. were criticised by American media

D. were supported by American media

问答题 简答题