每天一篇經濟學人
「 再忙也不忘充電 」
-Jan 17 th 2020 | 750 words-
在公眾號回復「pdf」獲取PDF原文和音頻
本次選文：「Science & technology」Watering deserts：Out of thin air在乾燥的空氣中憑空取水，這聽起來似乎像是魔法，科學卻實現了它。
沙漠中缺水，但空氣比比皆是。科學家發現，利用水蒸氣夜間液化原理，結合一些特定的吸附材料和化學反應，可以實現從空氣中取水。
「憑空」取水為生活在沙漠中的人找到一種取之不盡的「天然水庫」，若能實現規模化，沙漠就不再聞沙喪膽。
Science & technology—Watering deserts：Out of thin air
New techniques may help provide water in arid areas
→ out of thin air 雙關 1. out of nowhere, as if by magic憑空，無中生有；2. 文中取 字面意思. out of =from, thin air 稀薄的空氣; 即從空氣中儲水.
→ arid adj. 英 [ˈærɪd] having little or no rain; very dry. (of land or a climate 土地或氣候) 乾旱的；乾燥的. SYN waterless.
If you live in a desert, maintaining a supply of fresh water is a challenge. One answer is desalination, but that needs a source of brine from which to remove the salt—which in turn requires that your desert be near the sea. Even in inland deserts, though, moisture is often present in the air as water vapour. The problem is extracting this vapour effectively and cheaply. And that is what two groups of researchers— one at the University of Connecticut, the other at the University of California, Berkeley—hope they have managed to do.
→ desalination n. 英 [ˌdiːˌsælɪˈneɪʃn] the process of removing salt from sea water. （海水的）脫鹽. 記憶技巧：de 去掉 + salin 鹽 + ation 過程，結果 → 脫鹽.
→ brine n. sea water海水
→ moisture n. 英 [ˈmɔɪstʃə(r)] very small drops of water that are present in the air, on a surface or in a substance. 潮氣；水汽；
→ vapour n. 英 [ˈveɪpə(r)]. 同vapor[美]. a mass of very small drops of liquid in the air, for example steam. 蒸氣；潮氣；霧氣. water vapour. 水蒸氣.
The ease with which water can be won from air depends on that air’s relative humidity. This is a measure of its current vapour content as a percentage of its maximum possible vapour content at its current temperature. A relative humidity of 100% means the air in question is holding as much water vapour as it possibly can. A good way to get air to give up some of its moisture is therefore to cool it to the point where its relative humidity exceeds 100%.
→ humidity n. 英 [hjuːˈmɪdəti]. the amount of water in the air. （空氣中的）溼度.
→ in question under discussion or consideration 討論中的, 考慮中的.
Sometimes this happens naturally at night, causing mist and dew to form. These can be collected in special traps in areas where liquid water is otherwise rare. But if nocturnal cooling does not bring air all the way up to 100% relative humidity, building water traps out of special materials might give nature a helping hand.
→ mist n. a cloud of very small drops of water in the air just above the ground, that make it difficult to see. 薄霧；水汽.
→ dew n. the very small drops of water that form on the ground, etc. during the night. 露;露水.
→ nocturnal adj. [nɒkˈtɜːnl] of or relating to or occurring in the night 夜間發生的. noct- 'night'[用於元音字母前]表示「夜」.
→ give/lend sb a helping hand. be of assistance 助~ 一臂一力 SYN make a contribution.
Surface features
Adsorption is a process which plucks water molecules from air that has less than 100% relative humidity by attaching them to the surface of a solid material. The molecules are held there by electrostatic connections called Van der Waals forces that link them with the molecules of the pertinent surface. To collect a lot of water this way therefore requires a material that has two properties. One is a large surface area. The other is an appropriate Van der Waals response.
→ absorption n. [æb'sɔ:pʃən] 吸附；吸附作用；表面吸收 源自 adsorb v.
→ pluck v. pick, collect 採集. pluck from.
→ Van der Waals forces. 範德瓦爾斯力, 即範德華力. 分子間作用力的一種。是原子或分子間電偶極子-電偶極子相互作用：靜電力、誘導力和色散力的統稱。與共價鍵、離子鍵、金屬鍵相比，範德瓦爾斯力要弱得多，因此也稱弱力。範德瓦爾斯力也弱於氫鍵。
→ pertinent adj. 英 [ˈpɜːtɪnənt] Something that is pertinent is relevant to a particular subject. 有關的；相關的. SYN relevant.
→ property n. an attribute, quality, or characteristic of something特性，性能, 屬性SYN attribute, feature.
Experimental traps that employ this principle have been made using substances called metal-organic frameworks. These are porous molecular networks through which air can circulate. Their porosity gives them a huge surface area. And by picking the right ingredients, such as zirconium, they can be given the necessary Van der Waals properties. Zirconium is, however, costly.
→ metal-organic frameworks 有機金屬框架.
→ porous adj. 英 [ˈpɔːrəs] having many small holes that allow water or air to pass through slowly. 多孔的;透水的;透氣的. porosity n.(術語) 孔隙度；孔隙率；疏鬆
→ zirconium n. 化學元素(Zr) 鋯.
Moreover, once adsorbed, the water must then be released. This means warming the adsorptive material—the warmth being provided by the sun, once it has risen. Here, metal-organic frameworks present a problem. They tend to reflect sunlight rather than absorbing it, and so do not heat up well. To overcome this, engineers build solid 「foams」 made of copper into the system. These heat up in the sun and transfer some of their heat to parts of the adjacent metal-organic framework where adsorbed water needs to be released. This works, but adding such foams makes an already costly technology even dearer.
→ foam n. Foam consists of a mass of small bubbles that are formed when air and a liquid are mixed together. 泡沫;氣泡
→ adjacent adj. 英 [əˈdʒeɪsnt] next to or near sth. (of an area, a building, a room, etc. 地區、建築、房間等) 與…毗連的；鄰近的. ~ (to sth)
Both groups hope to get around these complications, but in different ways. The researchers at Berkeley, led by Omar Yaghi, announced their results last year. They propose to replace the zirconium-based metal-organic framework with one based on aluminium. Not only is aluminium cheaper than zirconium, it is better at binding to and then releasing water, making the trap’s operation smoother. On top of this, Dr Yaghi has found that by mixing graphite into the powder from which the framework is compounded, in order to make it black, and therefore heat-absorbing, he can eliminate the need for copper foam.
→ get around. 同get round[英]. to get around a problem or difficulty means to overcome it. 克服，解決（問題或困難）.[同義詞] overcome.
→ aluminium n. [ˌæljəˈmɪniəm]. 化學元素(Al) 鋁.
→ on top of this n. 在此基礎上.
→ graphite n. 英 [ˈɡræfaɪt] 石墨
In Connecticut, meanwhile, Steven Suib and his colleagues, who have just reported their result in Environmental Science and Technology Letters, propose getting rid of both framework and foam, and replacing them with birnessite, a type of manganese dioxide. Birnessite is abundant in nature. It is also easy to make artificially. It is therefore cheap.
→ birnessite n. 水鈉錳礦.
→ manganese n. 英 [ˈmæŋɡəniːz] 化學元素（Mn）錳
→ artificially adv. 英 [ˌɑːtɪˈfɪʃ(ə)li] not according to nature. 人工（造，為）地；不自然地. [同義詞]: unnaturally，by artificial means.
Like metal-organic frameworks, birnessite is riddled with tiny holes that allow air to move around inside it, to maximise adsorption. And it, too, is black and therefore heat-absorbing.
→ be riddled with. full of 充滿 ; riddled with holes滿是小洞的.
Both proposals work. Tested in desertlike conditions in a laboratory—and in Dr Yaghi’s case in an actual desert, too—they absorb and regurgitate reasonable fractions of their weight of water every day. They are nothing like as productive as desalination plants, and so would have to be built at large scale to generate water in commercially useful quantities. But one thing deserts do have is lots of cheap land. If either or both of these inventions can be manufactured at scale, then the deserts may bloom—if not with plants, at least with water-collection farms.
→ regurgitate v. 英 [rɪˈɡɜːdʒɪteɪt] If a person or animal regurgitates food, they bring it back up from their stomach before it has been digested. 反芻;使(食物)回湧.
→ nothing like (或 near) as (或 so)…as 遠不像…那樣…
→ bloom v. to appear or expand suddenly 大量出現. SYN burgeon.
據計算，全球大氣的含水量是地球上所有河流總量的8倍，所含的淡水資源非常豐富，不僅是霧、雲，無處不在的空氣中都有許多水分子的存在。如果在水資源匱乏的區域，利用這些空氣，那麼全球用水不再是問題。近幾十年來，科學家們也一直在努力研究從空氣中獲取淡水的方法。全球各國的科學家採用了多種不同的方法試圖從空氣中獲取水資源。適用於沙漠地帶的「人造山脈」法，其中人造山脈用玻璃纖維製成，外面塗上聚四氟乙烯，長10000米，寬1000米，高600米，利用溼潤空氣遇「山」後沿坡爬升，遇冷凝結成雨。前蘇聯科學家利用功率很大的噴霧機向空中噴水霧，並把霧噴到足夠的高度。上升氣流將水霧帶到高處，5分鐘後就會在3000米的高空形成堆積雲。噴水霧使空氣溫度降低，還會使空氣中原有的水汽凝結成細水滴。用這種方法向空中每噴射1噸的水霧，可以獲得1000噸的雨水。德國一家研究所研發了一種空氣轉化飲用水的設備，僅依靠太陽能供電供熱。其核心技術是利用鹽水的吸溼作用吸收空氣中的水分。讓鹽水從一個塔形裝置頂部流下，並在這一過程中吸收空氣中的溼氣。然後將鹽水泵入一個數米高的真空容器，再利用太陽能加熱因吸收溼氣而被稀釋的鹽水，蒸餾出不含鹽的水分。2017年，美國麻省理工學院和加利福尼亞大學伯克利分校的研究人員共同研製了一種僅利用太陽就能從空氣中吸取水資源的新裝置。這個裝置運用了一種金屬有機框架材料，金屬有機框架材料是一種新型材料，是一種有機配體和金屬離子或團簇通過配位鍵自組裝形成的具有分子內孔隙的有機-無機雜化材料。加拿大的一家公司生產出了一種利用納米技術從空氣中提取淡水的機器,被稱為「水資源收割機」。其水分收集部分運用了碳納米管，碳納米管直徑只有幾納米，它的上下有兩層不同的材料，上層是親水材料，下層則是疏水材料。當空氣中的水分接觸到該碳納米管上層，就會被親水的一層捕捉到，在碳納米管的毛細現象作用和重力作用下滲透到下層，由於內層疏水，在表面張力的作用下，這些水分會聚集成小水滴，小水滴會被收集到下方的收集器中。整個過程不需要任何額外的能量，並且無論在多乾旱的地區都能夠正常工作。更多詳解/翻譯訓練
見「每天一篇經濟學人」打卡訓練營
They are nothing like as productive as desalination plants, and so would have to be built at large scale to generate water in commercially useful quantities.
陶片放逐 | 「瘋子」川普 | 令後輩震驚的事
外資風投 | 澳洲大火 | 騰訊「鈔」能力 | 科技中國
字節跳動 | 年度精選 | 朝美僵局 | 科技發展
若過期添加微信：wyxqqq2016