使用半波整流电路进行避雷器的直流电导电流试验时,为了减小直流电压的脉动,需要在试品C

题型:单项选择题

问题:

使用半波整流电路进行避雷器的直流电导电流试验时,为了减小直流电压的脉动,需要在试品Cx上并联稳压电容C,其电容值采用下列电容值哪一较好()

A.10uF

B.0.1uF

C.0.01uF

考点:风电场安全风电场安全题库
题型:单项选择题
以下叙述正确的是(  )
A.平面直角坐标系下的每条直线一定有倾斜角与法向量,但是不一定都有斜率
B.平面上到两个定点的距离之和为同一个常数的轨迹一定是椭圆
C.直线l:x+y-1=0上有且仅有三个点到圆C:(x-3)2+y2=16的距离为2
D.点P是圆C:(x-4)2+y2=4上的任意一点,动点M分
OP
(O为坐标原点)的比为λ(λ>0),那么M的轨迹是有可能是椭圆
题型:单项选择题

信用活动中的货币发挥的职能是()。

A.储藏手段

B.支付手段

C.流通手段

D.价值尺度

题型:单项选择题

To Chinese immigrants, in the mid-1800s, California was “The Land of the Golden Mountain.” In their homeland they had heard the words, “There’s gold in California.” They sailed 7,000miles to join the gold rush and strike it rich. Between 1849 and 1882, more than 30,000 Chinese came to California. Most were men. They had been farmers in China. They came here to be miners and laborers. They ended up doing many other jobs, too.

Like many other immigrants, they did not plan to stay in America. They came because of their ties to their homeland and their families. They planned to return to China with their fortunes and help their families.

Only a few Chinese gold miners struck it rich. Most picked over the areas that had been mined already. But still, white miners resented the Chinese. Slowly, they drove the “yellow peril” from the mining camps.

By the end of the 1850s, many Chinese returned home. Those who stayed found other jobs.

Few women had come west in the gold rush. The Chinese saw a good business opportunity. They began doing the jobs women would have done. Many became house servants. Many more opened  laundries.

The Chinese opened restaurants. Chop suey and show mein are popular Chinese-American dishes. The Chinese probably created these dishes to serve to the white miners.

Other Chinese became fishermen, farmers, and even cigar makers.

1. Why did Chinese go to America in the mid-1800s?

A. Because they could find good jobs there.   B. Because they had found gold there.

C. Because they could open laundries and restaurants there.

2. The underlined word “resented” mean “________”.  

A. liked                        B. helped               C. hated                    D. served

3. Which should be the title of the passage?

A. Early Chinese immigrants in America     B. Dream to strike it rich

C. The difference between men and women   D. Gold miners in America

题型:单项选择题

根据新事物普及过程调查的结果,把大众传播过程区分为”信息流“和”影响流“的是()

A.卡兹

B.罗杰斯

C.克拉帕

D.贝雷尔森

题型:单项选择题

脑复苏时以下降温护理措施中哪项不正确?()

A.降温时间争取在5分钟之内

B.降温持续时间一般维持在2~3天

C.降温的方法宜采用头部重点降温

D.降温越深越好,最好低于28℃

E.复温时不宜太快,一般为24小时提升1℃~2℃

更多题库