开关电源主要采用PWM脉宽调制技术和PFM脉频调制技术。

题型:判断题

问题:

开关电源主要采用PWM脉宽调制技术和PFM脉频调制技术。

考点:通信电力机务员通信电力机务员题库
题型:判断题

保险资金的运用之所以可能,是因为保险收入与支出之间存在()。

A.时间滞差

B.数量滞差

C.来源滞差

D.给付滞差

E.收益滞差

题型:判断题

缺词填空(5分)

All over the world people e_______(1) sports. Sports help one to keep h______(2), happy, and to live longer. Many people like to watch o______(3) play games. They buy tickets or turn on their TVs to watch the games. Often they get very excited when “their” player or team w______(4).

Some sports are so i________(5)that people everywhere like them. For example,more and more young people like playing football.

Some sports or games such as running and jumping go back t______(6)of years. But basketball and v________(7) are rather new.

People from d_________(8) countries may not u_______(9)each other, but after a game together they often become good f______(10).

题型:判断题

细菌感染后,主要引起()

A.抗体产生

B.中性粒细胞或单核巨噬细胞浸润

C.B细胞产生IgE

D.T细胞介导的免疫

E.以上均正确

题型:判断题

老年甲状腺功能亢进,药物治疗后多次复发适合的治疗是

A.丙基硫氧嘧啶
B.他巴唑
C.131I治疗
D.甲状腺次全切除
E.碘盐治疗

题型:判断题

由于GS-I黏结剂属高分子热塑性材料,与同为髙分子材料的道路沥青有着较好的相似相容性,当施工沥青混合料时,在热拌沥青混合料的热作用和()下,GS-I膜部分熔化与热拌沥青混合料融为一体。

A.化合作用

B.复合作用

C.碾压作用

D.按压作用

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