问题 问答题 计算题

一台阳离子交换器,其直径为2.5m,树脂层高度为1.6m,树脂工作交换容量为800mol/m3,运行流速为15.0m/h,进水中Ca2+=2.42mmol/L,Mg2+=0.46mmol/L,Na++K+=0.54mmol/L,求周期制水量和实际运行时间。

答案

参考答案:

进水中含阳离子总量为:2.42+0.46+0.54=3.42mmol/L

树脂能够交换阳离子总量为:3.14×2.52/41.6×800=6280mol

周期制水量为:6280÷3.42=1836m3

实际运行时间为:1836÷(15×3.14×2.52/4)=25h

阅读理解

This morning, I went camping along a path in Green Natural Park with my friends. We were happy because it was a sunny day. We were expecting an enjoyable two-day holiday. On the way, we kept singing and making jokes.

However, in the afternoon, when we finished our picnic at one o’clock, it was dark and windy. Soon, there was a shower. Unluckily, none of us brought an umbrella. We ran about but we could find no place to hide.

Twenty minutes passed and it was still raining. There were hours to go before we reached the campsite (野营地). It was even worse that our small compass (指南针) showed that we went to the wrong way. We had lost our way!

We had to make a quick decision as it was raining heavily. Chris said we could set up a tent to hide in, so Mary and Tom helped to set up the tent. Chris and I tried to make a fire to keep us warm. But we were unable to light the fire, as everything was wet. We dried ourselves, chatted and waited inside the tent. At about five o’clock, it stopped raining. We decided to give up the camping trip because all of us had been very tired.

This camping trip may not be very successful but we know each other better. And the most important thing I’ve learned from this trip is the importance of team spirit.

小题1:The writer with his friends went camping in Green Natural Park ______.

A.to have a picnic

B.to have a shower

C.to enjoy a two-day holiday

D.to make jokes小题2:The writer thought it even worse that they ______.

A.had no picnic

B.lost their way

C.couldn’t light the fire

D.couldn’t know each other小题3:Which of the following is NOT true?

A.It was sunny in the morning.

B.None of them had an umbrella.

C.They gave up the camping at last.

D.They ran about to dry themselves.小题4:The writer has learned the importance of ______ from the trip.

A.making a decision

B.working together

C.enjoying holidays

D.taking a compass

单项选择题