24Sh-19型离心泵的铭牌上注明:在抽升20℃水温的水时,HS=2.5m,现问:

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问题:

24Sh-19型离心泵的铭牌上注明:在抽升20℃水温的水时,HS=2.5m,现问: ①该泵在实际使用中,是否其水泵吸入处的真实表值HV只要不大于2.5m水柱,就能够保证该泵在进行中不产生气蚀。 ②铭牌上HS=2.5m是否意味着,该泵叶轮中的绝对压力不能低于10.33-2.5=7.83m水柱高?为什么?请简述回答。

考点:水利工程泵与泵站泵与泵站题库
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In 1995, Oseola McCarty donated $ 150, 000 --most of the money she made in her lifetime--to the University of Southern Mississippi. She just wanted to help poor students. Her friends and neighbours were surprised at the news. McCarty was a good woman and was always friendly and 小题1: . But everyone in her town knew that she was not r 小题2:

Oseola McCarty was born in 1908. She had to leave school when she was eight to support her family by 小题3: other people's clothes. She made only a few dollars a day. Oseola washed the clothes by hand. Then she h 小题4: the clothes to dry. She did this for nearly 80 years. In the 1960s , when many people began to buy their own washers(洗衣机) and dryers(烘干机), McCarty didn’t have much work to do, so she started to iron clothes i 小题5: .

McCarty n 小题6: married or had children. Her life was simple. She went to work and to church. She had a black-and-white television, b 小题7: she didn’t watch it very often. It only had one channel. Oseola McCarty s小题8: money all her life and finally had about $ 250, 000.

In an interview with the University of Southern Mississippi News, McCarty said, "I can't do everything, but I can do s 小题9: to help somebody. And what I can do I will do. I wish I could do more." This quiet exceptional cleaning lady has 小题10:   the world a lesson in giving.

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双向扩散试验平板法中沉淀线弯向抗体则说明()

A.抗体分子量大

B.抗原分子量大

C.抗原与抗体量相等

D.抗原过剩

E.抗体和抗原皆不是单一成分

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多形红斑临床分型()

A.红斑-丘疹型

B.水疱-大疱型

C.Steven-Johnson综合征

D.落叶型

E.寻常型

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关于功血的病理生理,以下哪项不正确

A.青春期无排卵功血,FSH呈持续高水平,无LH高峰形成
B.围绝经期(更年期)无排卵功血,FSH和 LH同样升高
C.雌激素突破性出血是因为雌激素水平过高而无孕激素对抗
D.雌激素撤退性出血与外源性雌激素撤药后引起的出血类似
E.青春期功血与更年期功血的发病机制类似

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用紫外线灯管消毒物品,下列哪项是错误的

A.照射前应清扫尘埃

B.物品距灯管50~60cm

C.灯管用无水酒精纱布擦拭

D.灯亮开始计时

E.关灯后冷却3~4min再开

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