风痧的病变部位在（） A.肺卫 B.肺胃 C.肺心 D.肺脾 E.肺肾

(18分)

示波管是示波器的核心部分，它主要由电子枪、偏转系统和荧光屏三部分组成，如图14甲所示。电子枪具有释放电子并使电子聚集成束以及加速的作用；偏转系统使电子束发生偏转；电子束打在荧光屏上形成光迹。这三部分均封装于真空玻璃壳中。已知电子的电荷量=1.6×10C，质量=0.91×10kg，电子所受重力及电子之间的相互作用力均可忽略不计，不考虑相对论效应。

（1）电子枪的三级加速可简化为如图14乙所示的加速电场，若从阴极逸出电子的初速度可忽略不计，要使电子被加速后的动能达到16×10J，求加速电压为多大；

（2）电子被加速后进入偏转系统，若只考虑电子沿Y(竖直)方向的偏转情况，偏转系统可以简化为如图14丙所示的偏转电场。偏转电极的极板长=4.0cm，两板间距离=1.0cm，极板右端与荧光屏的距离=18cm，当在偏转电极上加的正弦交变电压时，如果电子进入偏转电场的初速度，求电子打在荧光屏上产生亮线的最大长度；

（3）如图14甲所示，电子枪中灯丝用来加热阴极，使阴极发射电子。控制栅极的电势比阴极的电势低，调节阴极与控制栅极之间的电压，可控制通过栅极电子的数量。现要使打在荧光屏上电子的数量增加，应如何调节阴极与控制栅极之间的电压。

电子枪中、和三个阳极除了对电子加速外，还共同完成对电子的聚焦作用，其中聚焦电场可简化为如图14丁所示的电场，图中的虚线是该电场的等势线。请简要说明聚焦电场如何实现对电子的聚焦作用。

语法填空。

    阅读下面短文,按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使用括号中词语的正确形式填空。

     My friend Vernon Davies kept birds. One day he phoned and told me he was going away for a week. He asked me to feed   1   birds for him and said that he would leave the key   2   his front door in my

mailbox.

       3   (fortunate), I forgot all about the birds until the night before Vernon was going to return. What

was worse,    4  was already dark when I arrived at his house. I soon found that the key Vernon gave

me could not unlock either the front door    5   the back door. I was getting desperate. I kept thinking

of   6  Vernon would say when he came back.

     I was just going to give up    7   I noticed that one bedroom window was slightly open. I found a

barrel and pushed in under the window. As the barrel was very heavy, I made a lot of noise. But in the

end, I managed to climb   8  and open the window.

     I actually had one leg inside the bedroom when I suddenly realized that someone   9  

(shine) a torch up at me. I looked down and saw a policeman and an old lady, one of Vernon's

neighbours. "What are you doing up there?" said the policeman.    10  (feel) like a complete fool, I

replied, "I was just going to feed Mr Davies' birds."

压力容器的压力等级分为：低压、中压、高压。

小兰在10月的一天早晨搭车去某地，发现当日大雾，沿途稍远的树木、道路看不清，接近城镇时，雾越来越小，经过城镇，基本无雾，再行，雾又越来越大。这种“田野有雾，城镇无雾”的现象是由于（）。

A.小镇上空尘埃稀少

B.地球近年升温

C.温室气体排放过多

D.小镇气温较高，形成热岛

党创办的第一份公开发行的中央机关报是什么？在哪一年创办？谁是第一任主编？