问题 问答题 简答题

请描述空间烧孔效应的物理过程。

答案

参考答案:当频率一定的纵模在腔内形成稳定振荡事产生一个驻波场。波腹处光强最大,波节处光强最小,消耗反转粒子数后,波腹处光强最小而波节处光强最大,则形成了空间烧孔。可见空间烧孔的形成过程由驻波腔和粒子空间转移慢引起的。

单项选择题
单项选择题

Many foreigners who have not visited Britain call all the inhabitants English, for they are used to thinking of the British Isles as England. (1) , the British Isles contain a variety of peoples, and only the people of England call themselves English. The others (2) to themselves as Welsh, Scottish, or Irish, (3) the case may be; they are often slightly annoyed (4) being classified as "English".

Even in England there are many (5) in regional character and speech. The chief (6) is between southern England and northern England. South of a (7) going from Bristol to London, people speak the type of English usually learnt by foreign students, (8) there are local variations.

Further north regional speech is usually " (9) " than that of southern Britain. Northerners are (10) to claim that they work harder than Southerners, and are more (11) They are open-hearted and hospitable; foreigners often find that they make friends with them (12) Northerners generally have hearty (13) : the visitor to Lancashire or Yorkshire, for instance, may look forward to receiving generous (14) at meal times.

In accent and character the people of the Midlands (15) a gradual change from the southern to the northern type of Englishman.

In Scotland the sound (16) by the letter "R" is generally a p sound, and "R" is often pronounced in words in which it would be (17) in southern English. The Scots are said to be a serious, cautious, thrifty people, (18) inventive and somewhat mystical. All the Celtic peoples of Britain (the Welsh, the Irish, the Scots) are frequently (19) as being more "fiery" than the English. They are (20) a race that is quite distinct from the English. (289 words)

Notes: fiery 暴躁的,易怒的。

(13)()

A.appetites

B.tastes

C.interests

D.senses