职称英语理工类考试完形填空： 重点文章Humidity
Not a plant to be seen， the desert ground is too 1 。 But the air contains water， and research scientists have found a 2 of obtaining drinking water from air humidity. The system is based completely on renewable energy and is therefore autonomous.
Cracks permeate the dried-out desert ground and the landscape bears testimony to the lack of water. But even here， where there are no lakes， rivers or groundwater， considerable quantities of water are stored in the air. In the Negev desert1 in Israel2， for example， annual average relative air humidity is 64 percent -- in every cubic meter of air there are 11.5 milliliters of water.
German research scientists have found a way of converting this air humidity autonomously into drinkable water. "The process we have developed is based exclusively on renewable energy sources such as thermal 3 collectors and photovoltaic cells， which makes this method completely energy-autonomous. It will therefore function in regions 4 there is no electrical infrastructure，" says Siegfried Egner， head of the research team. The principle of the 5 is as follows： hygroscopic brine — saline solution which absorbs moisture — runs down a tower-shaped unit and absorbs water from the air. It is then sucked into a tank a few meters 6 the ground in which a vacuum prevails4. Energy from solar collectors heats up the brine，， which is diluted by the water it has 7 。
Because of the vacuum， the boiling point of the liquid is 8 than it would be under normal atmospheric pressure. This effect is known from the mountains： as the atmospheric pressure 9 is lower than in the valley， water boils at temperatures 10 below 100℃。 The evaporated， non-saline water is condensed and runs down through a completely filled tube in a controlled manner. The gravity of this water column continuously produces the vacuum and so a vacuum pump is not needed. The reconcentrated brine runs down the tower surface 11 to absorb moisture from the air.
"The concept is suitable for various water 12 Single-person units and plants 13 water to entire hotels are conceivable，" says Egner. Prototypes have been built for both sys-tem components- air moisture absorption and vacuum evaporation-and the research scientists have already 14 their interplay on a laboratory scale. In a further step the researchers in-tend to develop a demonstration 15 。
练习：
1. A dry B dirty C sandy D clean
2. A path B way C channel D road
3. A oil B wood C coal D solar
4. A when B what 。 C where D who
5. A promise B progress C prospect D process
6. A of B with C off D below
7. A absorbed B attracted C allowed D affected
8. A wetter B hotter C lighter D lower
9. A close B there C beyond D nearby
10. A gradually B distinctly C necessarily D possibly
11. A again B too C either， D more
12. A users B owners C providers D producers
13. A using B obtaining C supplying D cleaning
14. A repaired B sold C copied D tested
15. A tank B method C facility D tool
答案：ABDCD CADBB AACDC
从空气湿度中获取饮用水
看不到任何植物，沙漠的土地干燥无比。但是空气中却含有水分，科学家们已经发现了从空气中获取饮用水的方法。这个系统完全依赖再生能源，因此也是自主独立工作的。
干透的沙漠表面上布满了裂痕，这一风景证实了水的缺失。但是甚至在这没有湖泊、小河和地下水的沙漠，相当大量的水却被存储在空气中。比如，在以色列的内盖夫沙漠，每年的相对空气湿润度是64%——在每立方米的空气中有11.5毫升的水。
德国的科学家已经发现了一种能自动将空气里的水转化成饮用水的方法。“我们所研究的这一过程完全依赖于可再生能源，比如说太阳能集热系统和光生伏打电池，这样就使这个过程完全的自主独立工作了。这一过程可以在那些没有电力设施的地方进行。”研究主管Siegfried Egner说。这个过程的原理如下：具有吸湿性的卤水——吸收湿气的盐水溶液——从高塔形状的装置中流下来吸收空气中的水分。然后被吸进一个离地面几公尺高的真空容器里。太阳能集热器中的能源把盐水加热，然后用盐水把吸收的水分稀释。
由于在真空状态下，水的沸点要比在正常大气压的时候低。这一效果也可以从山脉上得知，由于那里的气压比山谷的低，水在很明显低于1000C的时候就沸腾。这一蒸发过的、没有盐分的水被浓缩并且通过一个完全填满的管子有控制地流下来。水柱的重力不断地引起真空，所以真空管是不需要的。重新浓缩的盐水再次流下到塔的表面去吸收空气中的湿度。
“这一理念适合不同用水者，适合个人使用的吸湿制水机及可供整问酒店用水的吸湿制水厂是有望制造成功的。”Egner说。空气湿度吸收和真空蒸发——这两个系统的原型已经制成——科学家们已经在实验室规模验证了它们的交互作用。下一步科学家们想设计出一套演示设备。