有一长50m的倒虹吸管,若两水面差H=3m,要求输送流量Q=3m3/s,已知λ=0.

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问题:

有一长50m的倒虹吸管,若两水面差H=3m,要求输送流量Q=3m3/s,已知λ=0.03,ζ进口=0.5,ζ=0.65,ζ出口=1.0,试求管径d为多少?

考点:注册土木工程师港口与航道工程注册土木工程师(港口与航道工程)——流体力学
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已知方程ax2+bx+c=0有一根x1>0,求证:方程cx2+bx+a=0有一根x2,使得x1+x2≥2。

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在其他条件相同的条件下,( )的远期汇票对收款人最为有利。

A.出票后30天付款

B.提单签发日后30天付款

C.见票后30天付款

D.货到目的港后30天付款

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Kofi Annan says helping survivors of last week’’s earthquake and (1)________in the Indian Ocean is (2)________. The United Nations secretary-general says countries that have offered aid must (3)________and provide it. The offers add up to around (4)________dollars. United Nations officials say (5) ________of that is needed during the next six months.The concern about offers of international aid is (6)________. For example, the earthquake in Bam, Iran, in (7)________of 2003 killed more than (8) ________people. Countries and groups offered hundreds of millions of dollars (9) ________. The United Nations says it has (10)________only about (11)________dollars in aid received so far. Governments and organizations that offered help (12) ________that, however.On (13)________Mr. Annan met with world leaders in Jakarta, Indonesia to discuss aid for (14)________. The leaders discussed and (15)________the idea of (16)________owed by affected nations. But the leaders did not say they would do so. Some said that (17)________to survivors would be more helpful.Representatives of (18)________countries and international organizations attended the meeting in Jakarta. Officials say they will cooperate to develop (19)________ for the Indian Ocean and the (20)________.

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阀门定位器负作用调校输入100KPa的信号压力,则阀杆()

A.水平位置

B.走完全行程

C.回到零位

D.水平垂直

题型:问答题

将水壶的特性分别列举成名词特性、形容词特性和动词特性的方法属于:()

A.焦点法

B.形态分析法

C.主体附加法

D.特性列举法

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