局部阻力
参考答案:
当流体流过管道中的一些附件(阀门、弯头、三通、散热器)时,由于流动方向和速度的改变,产生局部旋涡和撞击,就要损失能量,称为局部损失。
The Tricounty Bridge was supposed to relieve traffic in East Countway County. Although the bridge was opened last year, traffic in the county has gotten worse over the last year. To relieve the traffic situation in East Countway, therefore, the traffic commission should order the Tricounty Bridge closed. Which of the following, if true, gives the most support to the conclusion of the passage above ?()
A. The increased traffic seen in East Countway over the last year is largely attributable to a large casino and resort hotel that opened for business shortly after the opening of the Tricounty Bridge.
B. The Tricounty Bridge allows inhabitants of heavily populated West Countway County to reach East Countway in less than a half-hour, as opposed to the two hours the trip required before the opening of the bridge.
C. The bridge is only open for the periods 7-9 a.m. and 3-5 p.m. on weekdays.
D. Ship captains on the Countway River have complained that the bridge disrupts shipping on the river, thereby hurting the local economy.
E. The bridge is unlikely ever to pay for itself with the current low toll payment.
“我不想变成上帝,或居住在永恒中,或者把天地抱在屋里,属于人的那种光荣就够了。我自己是凡人,我只要求凡人的幸福。”这句话()
①反映出追求世俗人生乐趣的愿望②与禁欲主义主张相矛盾
③反映了人文主义的思想主张④说明了人们对现世生活悲观绝望的态度
A.①④
B.②③④
C.①②③
D.①②③④